ELECTRICAL SERVICE UPGRADE
Checklist
REVISED 12/03/14
GENERAL
The purpose of this checklist is to clarify the minimum electrical code requirements when upgrading the
electrical service in a residential building.
The information provided in this document is general and intended as a guide only. Each project is unique
and additional requirements may be enforced as deemed appropriate.
TIP! Failure to complete items below prior to inspection may result in a re-inspection fee.
INSTALLATION
Electrical service equipment shall be installed in accordance with the manufacturer’s installation
instructions, the 2013 California Electrical Code, Article 230, and PG&E rules and regulations.
MINIMUM SERVICE SIZE
The minimum size electrical service for a residential dwelling is 100 amps. Service size is based on the
square footage of the dwelling, the larger the dwelling the larger the service.
MINIMUM SERVICE CONDUCTOR SIZE
The minimum size for service conductors for a 100 amp residential service is #4 AWG copper or #2 AWG
aluminum.
MINIMUM SERVICE GROUNDING CONDUCTOR SIZE
The minimum size grounding conductor (ground wire) for a 100 amp residential service is #8 AWG copper
or #6 AWG aluminum.
GROUNDING ELECTRODE
The grounding electrode (ground rod or UFER ground) for a 100 amp residential electric service shall
consist of one of the following:
1. 5/8” steel rod embedded in 8 feet of soil.
2. ½” non-ferrous metal rod embedded in 8 feet of soil.
3. 20 feet of ½” steel reinforcing rod encased in 2” of concrete near the bottom of a footing or not less
than 20 feet of #4 AWG bare copper wire encased in 2” of concrete near the bottom of a footing.
ALTERNATE GROUNDING ELECTRODE SYSTEMS
The electrical code permits alternate grounding electrode systems. Discuss your design with the Building
Inspection staff.
CITY OF SAN MATEO : : BUILDING DIVISION
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Page 1 of 2 : : 330 West 20 Ave : : San Mateo, CA 94403 : : 650 522-7172 : : www.cityofsanmateo.org : : Building.info@cityofsanmateo.org
GROUNDING OF RESIDENTAL ELECTRICAL SERVICES
The grounding conductor of all electrical services is required to be bonded to the grounding electrode
(ground rod or UFER) and to the metal underground water service piping within 5 feet of the entrance to
the dwelling. In addition, the hot/cold water pipe and gas pipe of the water heater are required to be
bonded together with a minimum of a #8 AWG copper conductor.
ELECTRIC SERVICE EQUIPMENT LOCATION
1. Meters and metering equipment will normally be located in an unfenced area outdoors and mounted
on or recessed in an exterior building wall.
2. Meters and metering equipment shall not be located within any single-family residence.
3. For single-family residences, meter locations are normally not permitted in garages.
4. Meters and metering equipment may be located in a meter room accessible through its own outside
doorway. Meters on exterior walls of bedrooms or bedroom closets should be avoided.
5. For single-family residences, the electric meter should normally be located in the same general area
as the gas meter.
METER HEIGHT
The requirements for meter height, which is the vertical distance between the horizontal center line of the
meter and the final ground level or standing surface, shall be a minimum of 48” and a maximum of 66”.
METER WORKING SPACE
The width of the clear working space in front of the electric service panel shall be a minimum of 3”. The
depth of the clear working space shall be a minimum of 36”. The minimum clear height is 78”.
SUB-PANELS
Sub-panels are not permitted in closets or in fire rated walls (i.e. wall between garage and dwelling).
PERMIT REQUIREMENTS
A permit is required for all new electric service installations and replacements. Permit applications are
available at the City’s website www.cityofsanmateo.org.
PERMIT FEES
The cost of a permit for anew or replacement electric service is $117.36 for services up to 200 amps.
INSPECTIONS
All new and replacement electric services require a City inspection and approval before PG&E will make
permanent connection to the electric system.
QUESTIONS
If you have questions, please contact a Building Inspector at 650 522-7172.
CITY OF SAN MATEO : : BUILDING DIVISION
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Page 2 of 2 : : 330 West 20 Ave : : San Mateo, CA 94403 : : 650 522-7172 : : www.cityofsanmateo.org : : Building.info@cityofsanmateo.org