02-658 C.M.R. ch. 9, § 12 - Electrical Wiring and Equipment

9.12.1 Basic Standards

The following standards must be met for the electrical wiring and equipment used in connection with solid fuel burning equipment:

9.12.1.1 The electrical wiring and equipment used must be installed in accordance with NFPA 70.

9.12.1.2 Safety control circuits must be two-wire, one side grounded, having a nominal voltage not exceeding 150 Volts. A safety control or protective device must be connected so as to interrupt the ungrounded conductor; and

9.12.1.3 The control circuit must 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.

9.12.2 Additional Standards: Automatic Feed

The following additional standards must be met for solid fuel burning appliances where the fuel is automatically fed:

9.12.2.1 Electrical Equipment, Required Control Switches

9.12.2.1.1 Thermal Electric Switches. A thermal cut-off switch must be wired into the burner circuit to shut off the burner in the event of a fire at the unit. The switch must be placed directly above the unit to be fired with the thermal element pointed downwards and must be placed at the front of the unit. The switch must be no lower than the highest point of the flue connector where it enters the chimney. The switch must 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 multi-appliance installation.

9.12.2.1.2 On multi-appliance installations the emergency and thermal electrical switches must 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 system.

[NOTE: An example of wiring for multi-appliance installations is illustrated in Figure 9-2.]

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9.12.2.2 Disconnect Switch. A burner disconnect switch must be placed within three (3) feet of the burner.

9.12.2.3 Emergency Switch

9.12.2.3.1 An identified switch to shut down the boiler, furnace or water heater in an emergency must be placed outside of and adjacent to the entrance to the room where the appliance is located.

9.12.2.3.2 If the entrance to the room where the appliance is located is only accessible from outdoors, the emergency switch may be placed inside not more than one (1) foot beyond the door opening.

Notes

02-658 C.M.R. ch. 9, § 12