Switch height for paddle fan
Q: Is there a minimum and maximum height for a wall switch that controls a paddle fan in a bedroom of a multifamily dwelling?
A: There are no special rules for the height of a wall switch that controls a ceiling fan. However, there are requirements for the height and location of ceiling-suspended (paddle) fans around swimming pools, bathtub and shower areas.
The general rule for the height of switches is in 404.8(A), which requires that switches be located in a readily accessible place. The operating handle cannot be more than 6 feet 7 inches above the floor or operating platform. The three exceptions following part (A) of 404.8 do not apply to this installation.
There is no minimum height specified in the National Electrical Code (NEC) for this wall switch, but it has to be readily accessible.
Door requirements for 2,000-ampere switchboard
Q: A 2,000-ampere, 208Y/120-volt service switchboard is required for a commercial building. It will be located in a large room where the wall will be about 10 feet from the front of the switchboard. Does the door leading into this room have to swing outward and be equipped with a pressure plate or panic hardware to comply with 110.26(C)(2)? The double doors to this space are metal-clad.
A: The doors to this room do not have to open in the direction of egress and do not need to be provided with panic bars or pressure plates to open. This opinion is based on paragraph (a) of 110.26(C)(2), which reads: “(a) Unobstructed exit. Where the location permits a continuous and unobstructed way of exit travel, a single entrance to the working space shall be permitted.” This entrance/exit does not need doors to satisfy the NEC; however, the area should be secure.
Luminaires in bathrooms
Q: Is it permissible to install a luminaire (lighting fixture) above a bathtub or shower stall?
A: The answer to this question is in 410.4(D). This part requires luminaires (lighting fixtures) that are suitable for damp locations or listed for wet locations where located within 8 feet above the rim of the bathtub or shower threshold and within 3 feet horizontally of these plumbing fixtures.
HACR circuit breaker for AC unit
Q: In a recent issue of ELECTRICAL CONTRACTOR magazine, there was a question about the use of an HACR type circuit breaker for a remote condensing unit. The nameplate specified an HACR type circuit breaker for the overcurrent protection, but a revision to the 2005 NEC no longer requires specially marked circuit breakers where two or more motors are connected to a single branch circuit.
A: My response was that an HACR type circuit breaker was no longer required by 430.53(C). I failed to mention 110.3(B), which requires that listed or labeled equipment be installed in accordance with instructions provided with the equipment. Therefore, the answer was incomplete and could be misleading.
The complete answer is as follows: Although an HACR type circuit breaker is no longer required by 430.53(C), the manufacturer’s instructions must be followed, and an HACR type circuit breaker must be provided to satisfy 110.3(B), or by special permission, the authority having jurisdiction may waive the requirement for an HACR circuit breaker under 90.4 of the NEC.
Wall space for receptacles
Q: In a bedroom in a dwelling unit, there is a 30-inch wall space that is covered by the entrance door when it is open. Is a receptacle required in this wall space?
A: The answer is yes, and the Code reference is 210.52(A)(1)(2) and (3). Part (A) requires receptacles in bedrooms and other rooms to be installed as required by parts (1), (2) and (3). Receptacles must be provided so that no space along the wall is more than 6 feet from an outlet.
A wall space is defined in (2) as “any space 600 mm (2 feet) or more in width (including space measured around corners) and unbroken along the floor line by doorways, fireplaces and similar openings.”
Where this 30-inch wall space is separated by a door on one side and an opening on the other side (an isolated 30-inch wall), a receptacle must be provided in that space, even though the space will be covered by the door when it is open. This is not a useless outlet as it can be used when a vacuum cleaner or floor polisher is used in the room. It may also be the only receptacle in the room that is not behind furniture.
Bathroom circuit receptacle rating
Q: Are receptacles in a bathroom in a dwelling unit required to be rated 20 amperes where used on the required 20-ampere branch circuit? Assume that there is only one duplex receptacle on this circuit.
A: Since a duplex receptacle is two receptacles on a single yoke or strap, the answer is no. Where a single receptacle is connected to a 20-ampere branch circuit that serves no other loads or receptacles, the ampere rating of the receptacle must be equal to the ampere rating of the circuit.
For a 20-ampere branch circuit, a 20-ampere receptacle is required. The NEC reference for this requirement is 210.21(B)(1) and reads: “A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.” The two exceptions to this rule do not apply to this installation.
Fifteen-ampere receptacles are permitted on 20-ampere multioutlet branch circuits by 210.21(B)(3), Table 210.21(B)(3), 210.24 and Table 210.24. The requirement for a 20-ampere branch circuit in the bathroom is in 210.11(C)(3) and allows more than one receptacle on this branch circuit.
Wiring methods in ducts or plenums
Q: I have to run wiring to a fan motor in a supply air duct in an office building. Is liquidtight flexible metal conduit permitted for this application?
A: Liquidtight flexible metal conduit is not permitted in ducts or plenums used for environmental air. Wiring methods that are recognized for this installation are in 300.22(B). This part covers wiring methods in ducts or plenums used for environmental air. Metallic wiring methods without an overall nonmetallic covering are the only types of wiring methods permitted.
These include Type MI cable, Type MC cable with a smooth or corrugated impervious metal sheath, rigid metal conduit, electrical metallic tubing, intermediate metal conduit, and not more than four feet of flexible metal conduit.
Permission to use flexible metal conduit is dependent on the need to connect physically adjustable equipment that is suitable for installation in the duct or plenum.
Flexible metal conduit may be used to supply the fan motor provided that the length of flexible metal conduit if the duct is not more than four feet and if connectors used to terminate the conduit in the duct effectively close any openings at the connections.
Size of equipment-grounding conductor
Q: I recently ran a branch circuit for a remote condensing unit that includes a fan motor and sealed hermetic refrigerant motor-compressor. Among other data, this information appears on the nameplate: 240 volts, single-phase; branch-circuit selection current—25 amperes; maximum fuse or HACR circuit breaker—40 amperes.
I used 12 AWG Type THWN copper conductors in schedule 80 PVC conduit with a 12 AWG copper equipment-grounding conductor. This branch circuit is protected with a 40-ampere 2-pole HACR circuit breaker as specified by the nameplate. I was told that I need a 10 AWG copper equipment-grounding conductor to comply with Table 250.122. Is this a correct interpretation?
A: Although it is true that a 10 AWG copper equipment-grounding conductor is required by Table 250.122, the text in 250.122(A) does not require compliance with the table under all conditions. This is the way one sentence reads in 250.122(A): “General. Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wire type shall not be smaller than shown in Table 250.122 but shall not be required to be larger than the circuit conductors supplying the equipment.”
Therefore, the 12 AWG copper equipment-grounding conductor does not have to be increased in size to satisfy the National Electrical Code.
Disconnect for deep fryer
Q: Is a disconnecting means required to be within sight of a deep fat fryer rated 6,000 watts, 240 volts, single-phase in a fast-food restaurant? The branch circuit conductors are 10 AWG copper and the overcurrent protection is a 30-ampere 2-pole circuit breaker.
A: Although information marked on the appliance for the maximum ampere rating of the branch circuit overcurrent protective device is lacking, the 30-ampere, 2-pole circuit breaker meets the requirements in 422.11(E)(3) because it does not exceed 150 percent of the appliance-rated current.
If the deep fat fryer has a switch with a marked off position, the branch circuit switch or circuit breaker where readily accessible is an acceptable disconnecting means [see 422.34(D)].
If the deep fat fryer does not have a switch with a marked off position, a disconnecting means must be provided within sight of the appliance or the circuit breaker must be capable of being locked in the off position. A revision to this requirement in the 2005 NEC requires that the locking means remains in place without the lock being installed. EC
FLACH, a regular contributing Code editor, is a former chief electrical inspector for New Orleans. He can be reached at 504.734.1720.