following standards must be met for the electrical wiring and equipment used in
connection with solid fuel burning equipment:
A. The electrical wiring and equipment used
shall be installed in accordance with NFPA #70 (National Electrical
B. Safety control circuits
shall be two-wire, one side grounded, having a nominal voltage not exceeding
150 Volts. A safety control or protective device shall be connected so as to
interrupt the ungrounded conductor; and
C. The control circuit shall be connected to
a power supply branch circuit fused at not more than the value appropriate for
the rating of any control or device included in the circuit.
The following additional
standards must be met for solid fuel burning appliances that are automatically
Electrical Equipment, Required
(1) Thermal Electric
Switches. A thermal cut-off switch shall be wired into the burner circuit to
shut off the burner in the event of a fire at the unit. The switch shall be
placed directly above the unit to be fired with the thermal element pointed
downwards and shall be placed at the front of the unit. The switch shall be no
lower than the highest point of the flue connector where it enters the chimney.
The switch shall be wired to shut-off the burner, circulating fan, forced or
induced draft fan and any remote fuel delivery device that is not an integral
part of the burner. A thermal electric switch is required for each unit in a
On multi-appliance installations the emergency and thermal electrical switches
shall be wired, in series through individual unit relays such that, if one
thermal switch or the "EMERGENCY" switch is open, the combustion air fan and
fuel delivery system will be shut off. This also applies if there are two or
more appliance rooms in the same building connected to a common fuel supply
Note: An example of wiring for multi-appliance
installations is illustrated in Figure SF-2.
here to view Image
A burner disconnect switch shall be placed within three (3)
feet of the burner.
identified switch to shut down the boiler, furnace or water heater in an
emergency shall be placed outside of and adjacent to the entrance to the room
where the appliance is located.
If the entrance to the boiler room is only accessible from outdoors, the
emergency switch may be placed inside not more than one (1) foot beyond the