General specification of earthing and equipotential bonding of bridge structures
General specification of
earthing and equipotential
bonding of bridge structures
The New Line Copenhagen – Ringsted
Alignment and Railway Technology
2012.06.29
Alignment and Railway Technology (ART-contract)
Page 1 of 20
General specification of earthing and equipotential bonding of bridge structures
General specification of
earthing and equipotential
bonding of bridge structures
The New Line Copenhagen – Ringsted
Alignment and Railway Technology
Copenhagen – Ringsted Team
Arne Jacobsens Allé 17
2300 København S
Version history of the document
02.00
00.02
Corrections according SAB
Jording ver. 02.00 /
21.02.2012
2012-06-29
XJGA
PLJ
XAHA
01.00 (2011-12-09)
00.01
English translation
2012-01-19
Fredericia
Sprogservice
PLJ
XJGAD
Ver. no. DK
Ver. no. UK
Description of
revision or change
Date
Prepared
Checked
Approved
Alignment and Railway Technology (ART-contract)
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General specification of earthing and equipotential bonding of bridge structures
Contents:
1
Purpose ....................................................................................................... 4
2
Norms .......................................................................................................... 4
3
Preconditions ............................................................................................... 5
3.1
Precondition for traction power supply ................................................................... 5
3.2
Other preconditions ............................................................................................... 5
4
BPU area ..................................................................................................... 6
4.1
Definition of the BPU area ..................................................................................... 6
4.2
Delimitation of the BPU area .................................................................................. 7
4.2.1
Objects not included in the BPU area ................................................................................... 7
4.2.2
BPU areas at bridges ............................................................................................................ 7
4.2.3
BPU areas at tunnels ............................................................................................................ 9
4.2.4
BPU areas at free line or station areas ................................................................................. 9
5
Carrying out of equipotential bonding .......................................................... 10
5.1
Equipotential bonding of objects in the BPU area .................................................. 10
5.1.1
Specification of cable for equipotential bondings. ................................................................. 11
5.1.2
Earthing of coherent or long objects ..................................................................................... 11
5.1.3
Equipotential bondings in areas of the Main line without booster transformer. .................... 11
5.1.4
Earthing of installations shared by S-train and Main line ...................................................... 12
5.1.5
System earthing in the BPU area .......................................................................................... 12
5.1.6
Pipes, cables and wires crossing the BPU area ................................................................... 13
5.1.7
Cables attached under bridge ............................................................................................... 13
5.2
Bridges and tunnels, small rebuildings ................................................................... 13
5.3
Bridges and tunnels, large or substantial rebuildings including new structures ...... 14
5.3.1
Concreting of pilot pipes for equipotentiel bonding cables ................................................... 16
6
Control measurement .................................................................................. 17
6.1
Contact voltage...................................................................................................... 17
6.2
Equipotential bonding ............................................................................................ 17
7
Annex........................................................................................................... 19
7.1
Annex 1 – Requirement analysis of equipotential bonding of small platform
reconstructions ...................................................................................................... 19
7.2
Annex 2 – TARTE_0_XXX_914_a ......................................................................... 20
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General specification of earthing and equipotential bonding of bridge structures
1
Purpose
The purpose of this note is to give foreign contractors including bridge/road
contractors the possibility to design as well as to build bridges and roads in
cooperation with the future electrified line Copenhagen – Ringsted in a way that
applicable standards, EN norms, railway norms, etc. within earthing and equipotential
bonding are complied with but also that they at an early stage of the designing can be
an incorporated part of the process.
This note thus describes the initiatives to be taken in regard to the future electrified
railway regarding equipotential bonding of bridge/road structures. The note will clarify
and define the BPU areas indicating solution suggests to how the BPU areas are
limited and how these are complied with, how corrosion may be prevented and how
the equipotential bonding should be carried out. The note also describes equipotential
bonding of conductive parts not directly included in a bridge structure, but are often
positioned in the close proximity.
2
Norms
Like future designing of earthing conditions in connection with bridge and road
structures, this note is subject to applicable norms and standards including:
EN 50122-1
Railway applications - Fixed installations - Electrical safety, earthing and the return circuit -Part 1: Protective provisions against electric shock.
BN1-105-1
FKI
Fjernbanens kørestrøms instruks, kap 2.4 (Traction power of the Main line, chapt. 2.4)
SAB Jording og potentialudligning på elektrificerede baner (SAB Earthing and
equipotential bonding of electrified railways), ver. 2
BN1-59-4
Belastnings - og beregningsforskrift for sporbærende broer og jordkonstruktioner (Charging
and calculation directions for track supporting bridges and earth structures)
BN2-83-2
Kørestrømsanlæg (Catenary systems)
Drifts- og beskyttelsesjording på Fjernbanen (Operation and protection earthing of the Main
line)
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General specification of earthing and equipotential bonding of bridge structures
3
Preconditions
This chapter describes the required presumed preconditions for notes
3.1
Precondition for traction power supply
It is expected that the new line section should be supplied with a traction power of
25kV AC, 50Hz.
The supply system may be carried out in various ways, though, of which the three
most likely are:
1. Supply using booster transformers
a. without feeder line or
b. with feeder line
2. Supply without using of booster transformers
a. without feeder line or
b. with feeder line.
3. Supply using autotransformers.
In case of supply by autotransformers or using feeder line, it should be anticipated that
any short circuit currents would be considerable larger than known from other
electrified Main lines in Denmark, therefore cables and structures shall be
dimensioned for this.
The cross section area of the equipotential bonding connectors has therefore not yet
been determined. The cross sections mentioned in this note are under the
precondition that a traction power supply is built equivalent to the existing electrified
lines.
3.2
Other preconditions
As the solution possibilities of the alignment have not yet been fully clarified, this note
might describe solution suggestions for bridge structures that may not be used in the
final project.
This note addresses the New Line between Copenhagen and Ringsted which is
established as a Main line. Therefore, the directions for earthing of the S-train are
described only to the extent that is relevant in relation to the Main line. Further
requirements for earthing of objects of the S-train are found in the stated norms of this
note, see chapt. 2.
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General specification of earthing and equipotential bonding of bridge structures
4
BPU area
This section describes the definition and delimitation of the BPU areas.
4.1
Definition of the BPU area
The contact and equipotential bonding area (the BPU area) is defined as the area
around the railway where electrical conductive parts and structures in connection with
the return current circuit are found.
Electrical conductive parts exceeding 2 m in the longitudinal direction of the track or 2
m at a right angle to the track or parts containing electrical components within the
contact wire or current collector zone are found in the BPU area.
The contact wire and current collector zones are illustrated in Figure 1.
Figure 1: The contact wire and current collector zones. The figure is from BN2-83-2
section 11.1, and the values X, Y & Z have been fixed to: X = 5.0m, Y = 2.5m, Z = 2.5m by
Banedanmark
All conductors, electrical components and structures found within 5 metres from the
centre of the closest electrified track, should be equipotentially bonded.
There must be no galvanic connection between conductive parts inside and outside
the BPU area. The reason being the prevention of stray currents flowing between the
BPU area and the external environment as well as any transmission of dangerous
voltages.
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General specification of earthing and equipotential bonding of bridge structures
In case of any conductive parts complying with the above mentioned requirements to
size, typically including metallic reinforcement of concrete structures or electrical
components closer than 2.5m to a part which is equipotential bonded in the BPU area,
these should be equipotentially bonded to the railway earthing and equipotentiel
busbar. It should be noticed that each time, a conductor is equipotentially bonded the
BPU area is increased, and this could result in required equipotential bonding
connections far away from the contact wire and current collector zones
In certain cases, the increase of the BPU area is not appropriate and instead, an
insulating fencing towards the conductive part could be established, that is outside the
limit of the BPU area to prevent personal risks from arising for example in case of a
broken contact wires or induced voltages.
4.2
Delimitation of the BPU area
The BPU area is delimited where this is considered the most obvious means of
mitigation in relation to the structure in question. It should be observed, though, that
the BPU area as a minimum should include the area in which objects are to be
equipotentially bonded.
4.2.1
Objects not included in the BPU area
Equipotential bonding of conductive parts which do not support or contain electrical
equipment is not required if the conductive part is smaller than 2m in the longitudinal
direction of the track. This applies for example manhole covers and wastepaper
baskets
4.2.2
BPU areas at bridges
Figure 2 shows a typical BPU area at bridges over railway.
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General specification of earthing and equipotential bonding of bridge structures
Figure 2: BPU area at bridges
The BPU area includes the total reinforced bridge structure and conductive parts in
contact with the bridge, e.g. a fence. Other typical conductive parts at structures could
be shielded cables, pipelines, crash barriers and lighting fixture.
Bridges at the BPU area should be considered as areas of public access in regard to
equipotential bonding cf. SAB jording og potentialudligning (SAB earthing and
equipotential bonding). This is owing to the fact that bridges normally consist of e.g.
metallic reinforced concrete and have fittings (like areas of public access), both
electrical and non-electrical within the contact wire zone.
In case of track supporting bridges it is not necessary to equipotentially bonding
lighting poles and other electrical installations placed under the bridge (shielded) if
these are positioned as a minimum 2.5m from another object which is equipotential
bonded. By the use of class I components it is necessary to ensure electric separation
between earth potential for the BPU-area and external low voltage installations.
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General specification of earthing and equipotential bonding of bridge structures
4.2.3
BPU areas at tunnels
Figure 3 shows the BPU area at railway tunnel.
Figure 3: BPU area at railway tunnel.
The BPU area in tunnel includes the total reinforced concrete structure.
In regard to equipotential bonding, tunnels at the BPU areas should be considered as
areas of public access. It is owing to the fact that tunnels often consist of e.g. concrete
reinforced with iron equipped with fittings (like areas of public access) both electrical
and non-electrical within the contact wire zone.
4.2.4
BPU areas at free line or station areas
The BPU areas at free line or stations areas are not treated in this note. Instead,
reference is made to SAB jording kap. 10 (SAB Earthing, chapt. 10).
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General specification of earthing and equipotential bonding of bridge structures
5
Carrying out of equipotential bonding
This section is treating how the exact equipotential bondings are carried out. Drawing
TARTE_0_XXX_914 in Bilag 2 (TARTE_0_XXX_914 of Annex 2) shows typical
objects and any equipotential bonding of these.
5.1
Equipotential bonding of objects in the BPU area
Within the BPU area, the following objects should be equipotentially bonded:
Conductive parts exceeding 2m in the longitudinal direction of the track or 2m
in a right angle to the track.
Objects containing electrical components.
The objects can be divided into two categories:
Primary equipotential bondings.
Secondary equipotential bondings.
In connection with bridge and tunnel structures, the reinforced bridge and/or tunnel
structures will fall under the primary equipotential bondings. Secondary equipotential
bondings will be conductive parts like for example lighting poles, railings, fences,
cables with conductive sheath and metallic pipelines. All earthings of a bridge, primary
as well as secondary, should be bonded to a common earthing and equipotential
busbar which is defined as primary earthing. Thereby, all earthing connections of a
bridge will become primary.
Annex 1 shows a requirement analysis for equipotential bonding at small rebuilding
of platform.. The requirement analysis is a flow diagram that briefly analyzes whether
an object should be equipotentially bonded. As bridge and tunnel structures are
equipotentially bonded the same way as platforms, the model gives a brief overview of
when an object should be equipotentially bonded.
2
Primary equipotential bondings are carried out using 4 pcs. 50mm green/yellow
copper cables. Each individual cable is connected to the return rail separately and a
sign is put up at the connection point of the 4 cables onto the structure. Secondary
2
equipotential bondings are carried out using one 50mm green/yellow copper cable.
The equipotential bondings are bolted onto the return rail using a Cembre connector
type AR 66D.
Equipotential bondings are established with an exceeding length of 40-50cm cable in
regard to any later track adjustment.
The railway earthing and equipotentiel busbar should be placed at a visible area
without public access, as an example at the end of a platform. The earthing and
equipotentiel busbar should be placed to enable inspection and control.
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General specification of earthing and equipotential bonding of bridge structures
5.1.1
Specification of cable for equipotential bondings.
1
The Main line:
The cable for equipotential bonding should be a 50mm2 copper cables. The cable should
be as type H07V-K, but with halogen-free green/yellow insulation, as an example like
NOVT 90 or similar cable.
The S-train:
2
Here, the equipotential bonding should be carried out by a 70mm copper cables. The
cable should be fitted with double covering. The external covering should be
green/yellow – alternatively, the internal covering should be yellow/green with grey
external covering, see BN2-84-1 page 9.
Banedanmark is currently looking at alternatives to the cables described above. At any
time only cables mandated by Banedanmark may be used.
5.1.2
Earthing of coherent or long objects
In case of various objects in the BPU area to be equipotentially bonded and if their
2
mutual distance is less than 2.5m , these should be connected to the return rail
through a common earthing and equipotentiel busbar to prevent dangerous voltages
for person. The connection to the railway earthing and equipotentiel busbar is carried
out in a way that the removal of one object does not result in disconnection of the
earth connection to other objects. Practically, this means that cables for equipotential
bondings must not be connected from one object to the next. An object should be
3
connected to the through-going equipotential bonding cable via compression clamps.
Long conductive structures in the BPU area like for example fences, rails or noise
barrier should be divided into electrically separated sections of 350m as a maximum.
Each section which is fully or partly within the BPU area should be earthed at the
centre of the section to the return rail. The separation between the sections should
consist of an electrically insulating section of 2.5m as a minimum with a 3cm
separation on either side. At gates or similar disconnection of the conductors, both
sides should be electrically connected so they have the same potential.
5.1.3
Equipotential bondings in areas of the Main line without booster transformer.
In case of equipotential bondings between the return current circuit of the Main line
and the equipotential bonding system for among other things bridge and tunnel
structures without installation of booster transformers in the Main line installation, the
two systems are connected through an VLD (Voltage Limiting Device). The VLD
1
Banedanmark is currently working on a technical notice describing that aluminium
cables will substitute copper cables. As the technical notice as of yet has not been
issued this report prescribes use of cables according to the regulations now in force.
2
According to BN2-83-2 Capt. 11.1.3 a distance of no less than 5 m is required. Other
norms, as SAB jording (capt. 2.3) states that the distance is 2,5 m. This report
complies with the latter.
3
See BN2-83-2 page 26 and 27. Note that earthing and equipotential busbar no
longer is allowed on the front of platforms.
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General specification of earthing and equipotential bonding of bridge structures
should short-circuit the connected systems at a voltage higher than 84V DC. When the
current passes 0A, the VLD should cut-off again.
5.1.4
Earthing of installations shared by S-train and Main line
Return circuit for S-train and Main line must not have direct connection. Structures
shared by the S-train and Main line, as an example bridges, are earthed to the
earthing and equipotentiel busbar of the Main line, which is connected through the
VLD to the return circuit of the Main line. The earthing and equipotentiel busbar are
also connected to the return circuit of the S-train through another VLD. The
connections between the earthing and equipotentiel busbar and return circuit of the
2
Main line are made using 4 pcs. 50mm green/yellow cables and at the return circuit of
2
the S-train, as a 1x70mm green/yellow cable.
The return circuit of the Main line is connected to the return circuit of the S-train
through a VLD.
The installation of a VLD at the bridge/tunnel is not necessary if a VLD is already
found within 500m. Cf. Banenorm BN2-84-1, a VLD should be installed for each
1000m where the S-train and Main line run in parallel. Reference is made to SAB
Jording kap. 10 (SAB Earthing, chapt.10)
5.1.5
System earthing in the BPU area
As this report is treating equipotential bondings at bridge and tunnel structures, the
system earthing of 400V installations will only be described briefly. For a more detailed
description of system earthing in BPU areas, reference is made to SAB Jording, kap 6
(SAB Earthing, chapt. 5)
Correct system earthing ensures that the earth potential is separated galvanically
between the BPU area and the surroundings. This prevents stray currents from the
railway from coming into the areas of the power plant, via for example cable shields or
PE-/PEN conductors. Stray currents may cause overcharge and unintentional heating
up of the cables.
Transformers placed within the BPU area must not supply consumers outside the BPU
area.
400V system earthing may be carried out in one of the below ways:
TT system earthing: When TT system earthing is used, a residual current
module type A should be installed (residual current relay to circuit breaker) in
the input section of the control board to protect against indirect contact. The
protection against indirect contact of the input section should be obtained by
double insulation. (class II).
TN-S system earthing: Either a 0.4/0.4kV isolating transformer or a dedicated
10/0.4kV transformer should be arranged. On the secondary side, the star
point is connected to the equipotentiel bonding cable / earthing and
equipotentiel busbar.
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General specification of earthing and equipotential bonding of bridge structures
5.1.6
Pipes, cables and wires crossing the BPU area
Cables and wires ”crossing” the BPU area should not be considered if these are not
having a direct electrical connection to the BPU area, i.e. if cables or wires are without
a metallic covering or placed in non-conducting pipes.
If cables and wires ”crossing” the BPU area are fitted with a conductive covering or
shield, the covering/shield should be cut-off at the limit of the BPU area.
Conductive pipes are insulated at the limit of the BPU area by an insulating flange or
piece.
5.1.7
Cables attached under bridge
If cables attached under bridge are crossing the contact wire within the contact wire
zone, these should be protected in one of the following ways:
The cables are placed in a conductive cable tray, the sides of which are
bigger or equivalent to the diameter of the cables.
The cables are placed in steel pipes.
The cable trays or steel pipe should be equipotentially bonded together with the bridge
or tunnel structure.
5.2
Bridges and tunnels, small rebuildings
Due to the normally good electrical conductivity of bridge and tunnel structures caused
by the metal reinforcement of the structures, the following initiatives should be taken
as a minimum even in relation to small rebuildings: (extract from SAB jording, side 19
(SAB Earthing, page 18))
BPU area should be defined.
In case of electrical fittings (class 1) at the bridge/tunnel, a HB connection
2
should be established (1G70mm Cu) between the main earthing and
equipotentiel busbar in the 400 V main switchboard and the railway earthing
and equipotentiel busbar This applies for bridges and tunnels also even
though the structure or the fitting have been placed outside the contact wire or
current collector zone.
Establishing of a railway earthing and equipotentiel busbar.
Establishing of an equipotential bonding connection/monitored DC/DC
cabinet/monitored AC/AC cabinet (dependent of railway type and locality)
between the railway earthing and equipotentiel busbar l and the return circuit.
Establishing of an equipotential bonding connection between the railway
earthing and equipotentiel busbar and the new/rebuilt structure or fitting.
Whether this connection should be established if the structure or fitting is
installed outside the contact wire or current collector zones will be determined
by TSA of Banedanmark.
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General specification of earthing and equipotential bonding of bridge structures
5.3
Bridges and tunnels, large or substantial rebuildings including
new structures
When making large or substantial rebuildings as well as new bridges and tunnel
structures, equipotential bonding should be made according to the applicable norms
and standards which this note makes reference to. Figure 4 and figure 5 shows typical
equipotential bondings at bridge structures and in tunnels respectively.
Figure 4: Typical equipotential bondings in relation to bridge structures. Diagonal Cu
conductor under bridge floor is not shown in the figure. Figure from BN2-83-2.
Metallic reinforced bridges are according to DS/EN 50122-1 to be considered as partly
conductive. A prerequisite is that the reinforcement is not accessible.
Metallic reinforcement in concrete is considered a conductor. If the concrete structure
is situated within the contact wire or current collector zone, this implies that the
reinforcement must be electrically coherent throughout the construction and through
earthing points connected to the return circuit.
The metallic reinforcement is made coherent by the use of cross clamps or spot
welding in at least one point for each reinforcement rod effectively creating a single
interconnected grid. Unless otherwise stated only the layer of the reinforcement
closest to the track need to be interconnected. As an alternative to the usage of cross
clams or spot welds pre-welded reinforcement grid can be used.
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General specification of earthing and equipotential bonding of bridge structures
The method described in BN1-59-4 is still applicable, provided that cross clams are
used:
In all new concrete bridges or new concrete bridge floors under which tracks
are passing – irrespective of the track is electrified or planned to be – a
2
copper rod or a bare copper wire of an area of 70 mm should be mounted
(both Main lines and S-trains)
o The copper conductor is mounted at the lower surface of the bridge
armouring and is fixed to the lower layer of reinforcement using cross
clamps. (In case of beam built-up, one conductor is mounted at the
lower surface of the centre beam of each span where track
positioning is planned or is possible).
o The copper conductor is tied with a small enough distance between
the attachment points to fit closely and levelled with the US
armouring.
o One copper conductor is positioned diagonally under the bridge floor
with a length from the bending point of the armouring to the similar
point of the opposite facade. .
o One copper conductor is positioned in each span where there are
tracks or tracks are planned.
o The copper conductor is connected to the earthing and equipotentiel
busbar like any other fitting according to BN2-84, BN1-105 or BN1106.
o The bridge topping is not increased due to the copper conductor.
2
On new track supporting bridges a similar 70 mm copper conductor is
mounted diagonally to the bridge floor onto the upper side of the top layer of
reinforcement using cross clamps for it to fit closely and levelled with the layer
of reinforcement. The copper conductor is connected to the earthing and
equipotentiel busbar.
Concrete structures shorter than 15 m in the longitudal direction and 2 m
perpendicular to the track are considered a minor structure and only partly conductive
and because of that not in need of equpotential bonding. However, reinforced
structures placed in close proximity to one another and with a total length exceeding
the previously mentioned 15 m and 2 m must be equipotential bonded. If the
reinforcement in the concrete structure is not connected to the return circuit, it is
necessary to mount all conductive parts separated from the reinforcement. The reason
is that concrete structures can only be considered partly conductive. All conductive
parts need equipotential bonding including small conductive parts with a vertical less
than 2 m.
On bridges the top side always needs equpotential bonding if the bridge is partly
within the contact wire or current collector zone in order to control differences in
potential. Pre-stressed concrete does not need equipotential bonding but the
reinforcement must not be assessable. On bridges made of pre-stressed concrete,
measures are to taken to ensure equipotential bonding of the top side of the bridges.
That could be placing a metal plate above the pre-stressed concrete or imbed a
welded reinforcement grid in a thin layer of concrete on top of the pre-stressed
concrete.
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General specification of earthing and equipotential bonding of bridge structures
Figure 5: Typical equipotential bondings in relation to tunnel structures.
Long tunnels are sectioned and earthing and equipotentiel busbars are established in
each of the sections. The metallic reinforcement on all sides of the tunnel is
equipotentially bonded.
5.3.1
Concreting of pilot pipes for equipotentiel bonding cables
When establishing of new bridges, pipes should be concreted for equipotential
bonding cables. (Extract from BN1-59-4):
Pilot pipes should be concreted into all new bridges so that it is possible to draw
equipotentiel bonding cables to all relevant fittings (rails, crash barriers, signs, lighting
poles, etc.) according to BN2-84, BN1-105 & BN1-106. The pilot pipes are left with
internal pulling thread. The pilot pipes are concreted downgrading with mouths
pointing down to prevent water filling.
Pilot pipes should end at an earthing and equipotentiel busbar from where connection
can be made to the return rail. On road supporting bridges, the earthing and
equipotentiel busbar is placed at terrain onto a surface of the structure facing towards
the track.
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General specification of earthing and equipotential bonding of bridge structures
6
Control measurement
6.1
Contact voltage
The highest permitted contact voltage has been fixed to 60V RMS according to EN
50122-1. The contractor who carries out the equipotential bonding may be requested
to verify that this voltage is not exceeded.
6.2
Equipotential bonding
As the touch voltage between an equipotentially bonded part and the return circuit is
the result of the summed up resistance of both directions to and from the railway
transformator to the equipotentially bonded object, it is not possible to state a common
result for the maximum resistance that is to be observed. Instead, the contractor who
carries out the equipotential bonding should verify by control measurements that the
equipotential bondings comply with the applicable regulations as stated in this note.
The control measurements should be made for objects in the BPU area that are
equipotentially bonded to the earthing and equipotentiel busbar. In connection with the
equipotential bondings of bridge structures, measurements should be made from the
earthing and equipotentiel busbar to:
Each section of the bridge structure
Objects placed on the bridge structure, like:
o Fences and rails
o Shieldings
o Lighting masts, etc.
By control measurements it should be ensured that each section is coherent. This
means that already at the building stage of the bridge, it should be ensured that these
measurements are feasible by concreting earthing points for measurement of the
electrical coherence of the armouring. The concreting of earthing points should be
carried out for the measurement to be made over de longest distance of the
armouring. See Figure 6.
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General specification of earthing and equipotential bonding of bridge structures
Figure 6: Measurement of the forward resistance of concrete section
According to "IEC/EN/DS 62305-3 Lynbeskyttelse af bygninger og anlæg" (IEC/EN/DS
62305-3 Lightning protection of buildings and equipment), the electrical resistance
through the section must not exceed 0.2Ω.
The electrical resistance to equipotentially bonded objects where the equalizing is
2
made using 50mm copper must not exceed 0.35mΩ/m.
Electrical connection to insulated objects within the BPU area should be control
measured, too.
As documentation of the control measurements, the results from the control
measurements should be entered into a measuring programme.
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General specification of earthing and equipotential bonding of bridge structures
7
Annex
7.1
Annex 1 – Requirement analysis of equipotential bonding of small
platform reconstructions4
4
Source: SAB Jording, figure 4
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General specification of earthing and equipotential bonding of bridge structures
7.2
Annex 2 – TARTE_0_XXX_914_a
TARTE_0_XXX_914_a, Princip for potentialudligning og beskyttelsesjording
(TARTE_0_XXX_914_a, Principle for equipotential bonding and protective earthing).
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