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Chapter 1

Table 5 Clearances for padmount transformers

Feature Clearance distance
Combustible walls or roof (including stucco). 10 feet (3 feet from a
combustible wall if using
a reduced flammability
transformer).
See Figure 4.
Noncombustible walls (including brick, concrete, 3 feet. See Figure 4.
steel, and stone), provided the side of the
transformer facing the wall does not have doors.
Materials that pass UBC Standard 2-1 or ASTM
E136-79 are considered to be noncombustible.
Fire sprinkler valves, standpipes, and fire hydrants. 6 feet. See Figure 3

Doors, windows, vents, fire escapes, and other 10 feet. See Figure 3.
building openings.
The water’s edge of a swimming pool or any body 15 feet. See Figure 3.
of water.
Individual domestic and irrigation wells. 100 feet. See Figure 3.
Facilities used to dispense or store LP or 20 feet. See Figure 5.
hazardous liquids or fuels. 10 feet. See Figure 5.
Gas service meter relief vents. 3 feet. See Figure 3.

Figure 3 Clearances for transformers

100'
WELL HEAD
15'
POOLS OR BODIES
OF WATER
TRANSFORMER

DOOR, WINDOW,
VENT OR OTHER
OPENING 10'
GAS
METER SPRINKLER
RELIEF VALVE,
VENT STANDPIPE,
OR HYDRANT
3'
FUEL TANK
6'
10' FIRE ESCAPE
TRANSFORMER

20'

Electric Service Handbook 2017 — Single-Family Residential Projects 12