Your Condo | Electricity
Replacing Your Transfer Switch
BY MARK MARMER
DURING the last year we completed several transfer switch
replacements, a repair due to water damage, several evaluations and a number of ongoing quotations. These tend to
be complex jobs and I often get the same questions from
managers about the switches and the logistics involved in
changing these devices. Let me run you through some of the
planning issues and see if we can cover most of the questions.
What is a transfer switch?
Most condominium buildings have a backup generator
to provide some electricity in the event of a utility power
failure. This emergency power is intended to maintain
life safety systems, such as the fire alarm, critical fans and
pumps, one or more of the elevators and some lighting.
The key piece of equipment that connects the generator to
the building’s power system is the transfer switch. The transfer switch monitors the utility power. If the utility power is
interrupted, the transfer switch will start the generator. Once
the generator is fully running, the transfer switch will open
the utility line and connect to the generator power.
Once the utility power comes back on the sequence
is reversed and the generator will turn off after a cool
down period.
What we often find is that the electronic control board
in the unit is no longer functioning properly. In a newer
unit we can sometimes replace this board. However, most
of these failures are in older switches and parts are no
longer available. At this point, we are often left with no
other option than a complete replacement.
How could an elevator upgrade impact on
the transfer switch?
In newer buildings the transfer switches have what’s
called, pre- and post-transfer. This is an interconnection
with the elevator controls. The transfer switch will give
the elevator a warning before each change of state to allow
the elevator to return to a safe location, perhaps the lobby.
This assists with the smooth operation of the elevators
and reduces the likelihood that someone will be stuck in an
elevator during a transfer. Again in many cases the switches
cannot be retrofitted to include this pre- and post-transfer
Why would I replace my transfer switch?
The equipment in our electrical rooms looks pretty
robust. We rarely hear of a wholesale need to replace all
the equipment protecting our building. Perhaps a thermographic inspection might lead to a tightening or minor
repair in the switchgear. So does this same level of confidence apply to the transfer switch?
Most of the switchgear is fairly mechanical and static.
The transfer switch is different. These switches have sensitive electronic circuit boards for monitoring the power as
well as a motor that drives the switch to open and close.
In short there’s a lot more that can go wrong.
There are usually two reasons that a transfer switch
needs to be replaced. The most common is an equipment
malfunction: the switch will either not transfer to generator power or perhaps not switch back to utility power.
The other relates to elevator upgrades.
If the switch is not functioning properly
can it be repaired?
Of course most managers and boards would opt for a
repair over a replacement. Once there’s a question of reliability, we need to perform an onsite evaluation in order
to decide how best to proceed.
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option. In that case a complete replacement may be the only viable solution.
Left: small TS Before
Right: small TS After
How much will it cost to
replace my transfer switch?
This cost will vary depending on
the size of the transfer switch and the
complexity of the work involved to
change it. Perhaps it’s best to review
these costs with your engineer and see
if the transfer switch has been included
in the reserve fund study. If so, what
kind of lifespan has been allowed and
is that an accurate estimation?
Will my building be without
power when the transfer
switch is replaced?
This is the single most common
question. Even without the transfer
switch in place the non-emergency
building power does not need to be
disrupted. That means that the suites
will have continuous power and most
of the lights will remain on.
The concern here is for the critical
emergency circuits that I mentioned
before. With the transfer switch
removed there would be no means
of connecting the generator to the
emergency power. This would leave
the building without its firefighter
elevator (or maybe all the elevators)
or fire alarm. Clearly, this could lead
to a disastrous situation.
How can we make sure that
the emergency power will
operate during the switch
change?
The solution is a rental generator to
provide power to these circuits during
the change. While this sounds fairly
simple and perhaps obvious there are
a number of factors to consider in the
planning stage.
• The placement of the generator is
critical. We have to avoid disruption
to traffic and minimize the noise that
may irritate residents.
• Cables will need to be run to
connect the generator to the building’s emergency power. These are
often placed in advance to minimize
the downtime on the day the work is
being done.
• The rental generator will need
an ESA inspection, separate from
the transfer switch. This needs to be
coordinated in advance as well to
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Left: large TS Before
Right: large TS After
keep the job moving smoothly.
• The generator needs fuel. If the
job takes more than one day a fuel
delivery may be necessary.
• While the generator is connected
and disconnected there will be a
disruption of the emergency power.
This may mean a short wait to use the
elevators. Information signs should be
posted in advance to warn residents.
Are there any other planning issues?
Here are some questions to better
qualify the contractor you select for
this type of project.
• Delivery. How will the new
switch get set in place and how far
in advance should it arrive on site?
• Time. How long will it take to do
this job? You need enough labour to
meet your projected timeline.
• Who will commission the transfer switch? This needs to be done in
conjunction with a qualified generator contractor.
• Coordinating the ESA inspection for this life safety device prior
to start-up is a small but critical step.
A large multi-storey building such
as a condominium contains a number
of critical and complex systems that
need to work in conjunction to
provide a safe and comfortable environment. These transfer switches are
one piece of the puzzle.
Sometimes it’s only when
a component fails that we
realize its importance.
Hopefully this brief overview will
put the property manager in a position to ask questions of their generator
contractor, electrical contractor and
engineer about the transfer switch and
to be able to plan for a change, that at
some point will be inevitable. v
Mark Marmer is
president of Signature Electric. He
can be reached at
416.490.8093