Section 658-13-8 - Electrical Wiring and Equipment13.8.1Code Compliance; General RequirementsThe following requirements must be met with respect to the electrical wiring and equipment used in connection with propane or natural gas burning equipment:
1. The electrical wiring and equipment used must be installed in accordance with NFPA 70;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; and3. 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.4. Whenever a furnace, direct-fired hot water heater, or boiler is installed, each unit must have its own dedicated electrical circuit.13.8.2Emergency Switch13.8.2.1 For central heating equipment and water heating appliances where the interruption of an electrical circuit will arrest the combustion process, an identified emergency shutdown switch must be placed outside of and adjacent to the entrance of the room where the appliance is located.13.8.2.2 An emergency switch shall not be placed outside of any building.13.8.2.3 If the entrance to the boiler room is only accessible from the outside, the emergency switch may be placed at the inside not more than one foot beyond the door opening.13.8.2.4 On multi-unit installations of commercial and industrial equipment, the emergency switch must be installed in accordance with Figure 13-1.13.8.2.5 On multi-unit installations, in other than one- and two-family residences, the emergency shut-off switch must be placed at the outside entrance of the room containing the appliances. The emergency switch must be wired so that, if the emergency switch is opened, all central heating equipment and water heating appliances (within that room) where the interruption of an electrical circuit will arrest the combustion process will be rendered inoperable. Where there are other (new or existing) multi-unit appliance rooms in the same building, those rooms must also be made compliant with this requirement. Click to view image
13.8.3Service SwitchFor central heating equipment and water heating appliances where the interruption of an electrical circuit will arrest the combustion process, a service disconnect switch for control of the burner while observing the flame must be placed at the unit, within three (3) feet of the burner.
13.8.4Thermal Cut-Off Switches13.8.4.1 For central heating equipment and water heating appliances where the interruption of an electrical circuit will arrest the combustion process, 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 at the highest point directly above the unit to be fired with the thermal element pointed downwards, and must be placed on the bottom of the floor joist or stringer at the front of the unit. In no case shall it be lower than the point where the flue connector enters the chimney. The switch must be wired to shut off the burner, circulating fan, forced or induced draft fan and any electrically-operated gas valves. A thermal electric switch is required for each electrically-powered gas-fired unit in a multi-appliance installation.13.8.4.2 On multi-unit installations other than one- and two-family residences the thermal electrical switches must be wired in series through individual unit relays so that, if one switch is opened, all equipment will be rendered inoperable.13.8.5Controls Containing MercuryThermostats containing mercury must be disposed of according to all federal and state regulations. (Refer to 38 M.R.S. §1663 and check with your local supplier.)
02-658 C.M.R. ch. 13, § 8