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Furnace plugged into the wall

DMartin

DMartin

Registered User
Joined
Jun 28, 2019
Messages
96
Location
Newton Kansas
Good day,
I have a commercial building I looked at today where they had attached a plug to the furnace and plugged it into a receptacle. It doesn't seem safe and I have told him I cannot accept it. Not being a licensed electrician myself he argues he has done this before. New to inspections and do not want to incur undue costs. Is this allowed? I am still learning to read the NEC if someone could help me out with the citation so I can enforce this it would be much appreciated. For one the appliance is more that 100" from the breaker box and not in clear sight I do not see how a plug can be sufficient for a cutoff. they want to use this in lou of a cutoff switch. I am looking at Article 422 but I do not see anything except for that 422.12 states it must be connected by individual branch circuit. But if the receptacle is on its own circuit?
 
Did some digging and I looks like the only appliances allowed to use a flexible cords are stated in 422.16 and well a furnace is not included in that list. I have read several forums where they state this is a norm. Kind of Crazy. does anyone else run into this and do you allow the practice?
 
If a commercial bldg. I assume the furnace to be rather large as in requiring greater than 110v?
 
Article 100: Disconnecting Means. A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

A receptacle is a device that disconnects the source of supply.

422.16 (A) Flexible cord shall be permitted (1) for the connection of appliances to facilitate interchange or to prevent the transmission of noise or vibration or (2) to facilitate the removal or disconnection of appliances that are fastened in place, where fastening means and mechanical connections are specifically designed to permit ready removal for maintenance or repair and the appliance is * identified for flexible cord connection.

*manufactures installation manual.
 
NEC 2014 (A) Flexible Cords. has the word "Frequent" interchange.

Apparently the code verbiage has changed.
 
Rick18071 said:
Article 100: Disconnecting Means. A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

A receptacle is a device that disconnects the source of supply.

422.16 (A) Flexible cord shall be permitted (1) for the connection of appliances to facilitate interchange or to prevent the transmission of noise or vibration or (2) to facilitate the removal or disconnection of appliances that are fastened in place, where fastening means and mechanical connections are specifically designed to permit ready removal for maintenance or repair and the appliance is * identified for flexible cord connection.

*manufactures installation manual.
Click to expand...
But (B) on there gives the specific appliances allowed and it is the normal ones we see plugged in Disposal, DW, Wall oven, and range hood. I would have to go back and look at manufacturer spec on the appliance but I would assume it does not state to plug it in.
 
Granted house fires start from hard wires too, but I don't know how many times I have seen burnt plugs from arching. Granted this will probably not be pulled in and out as much as most but it is in a mechanical room with the mop sink so people will be going in and out frequently. It is just new to me to see it connected this way.
 
Require the manufacture install instructions

See what they say about wiring it!!!!
 
It comes down to the Listing. Most, if not all, furnaces were not evaluated with a cord and attachment plug. They leave the factory without a cord and attachment plug. We used to require hard wiring but about ten years ago we gave up and started accepting cord and plug. We do require 12awg wire....which they never have.

I do not have a good reason but I don't think I would allow a cord and plug in a commercial setting. I'm not a fan of cord and plug disconnects because I had one melt and turn to putty as I tried to unplug it. It was so many years ago that I can't remember what it was attached to. It's an unpleasant experience.

48318437521_81c103b1aa_b.jpg

48318556422_188799bf2d.jpg
 
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Didn’t know that table existed. However, allowing that a 14 awg might qualify for 18 amps if it is in a closet, too often the overcurrent protection is 20 amps. If placed in an attic, the temperature correction brings it below 15 amps.
We could go look at the circuit breaker to determine if it is 15 amps if the furnace is in a closet. Then we could find out what cord designation we are dealing with. And then if all things line up one in 20 could have a 14awg cord. Not going to happen. When contractors complain about changing an illegal cord with another illegal cord I change the correction to “hard wire with a disconnect”.
 
400.7 Uses Permitted
(A) Uses . Flexible cords and cables shall be used only for the
following:
(1) Pendants.
(2) Wiring of luminaires.
(3) Connection of portable luminaires, portable and mobile
signs, or appliances.
(4) Elevator cables.
(5) Wiring of cranes and hoists.
(6) Connection of utilization equipment to facilitate frequent
interchange.
(7) Prevention of the transmission of noise or vibration.
(8) Appliances where the fastening means and mechanical
connections are specifically designed to permit ready
removal for maintenance and repair, and the appliance is
intended or identified for flexible cord connection.
(9) Connection of moving parts.
(10) Where specifically permitted elsewhere in this Code.

Not listed here!

I think this was all started by the generator craze and the code hasn't changed to allow?

I for one do not see a reason for a furnace to be pug and cord, and if your allowing this set-up it should be on a dedicated receptacle not a duplex. I currently have a roughed-in furnace done this way, I'm being told by the contractor it will be changed out at final...we'll see?

Just another aggravation.:mad:
 
It is on a dedicated circuit with a single receptacle. my concern is there is also going to be a gas WH. disconnect is required and some could argue that a plug is a form of disconnect, but I have seen plugs arch and if there was a gas leak in the room and some one hastily pulls the plug out this could cause an ignition source in the room. there are arguments on both sides every where I look, and I understand some in agreement in case you need to run a generator. but being an insurance company I highly doubt there will be a generator handy. I think the electrician just didn't want to fight with the spacing limitations he had and wants an easy way out.
 
NEC 422.33, Disconnection or PERMANENTLY connected appliances, see A & C

Since the NEC does not call out the furnace or water heater, I think the key here is NEC 422.31 Disconnection or PERMANENTLY connected appliances. Rating: 1/8 HP and not over 300-Volts-Amperes. And I'd throw in the old saying "What ever the manufactures requires or sez!"

Over 300 Volt-Amperes, it specifically states in NEC 422.31 (B) branch circuit switch or circuit breaker is within site. Also see NEC 422.32

I once inspected a small Rheem WH with less than 300V that came with a pre-wired plug and cord.

The garbage disposal and DW is typically over 1/8 hp and uses a cord and plug.

What household appliances use this small of HP? Scratching.....picking... scratching again?

Your wife's Kitchen-aid mixer has a 1.3 HP motor, with plug and cord but it's not a permanent fixture it just looks like one on the counter! You could probably run the wheels of a go-cart with that HP...er....er.....
 
@ ~ @

DMartin,

Are you saying that they will have a gas Water Heater and a [ fully ]
electric furnace, or is there a gas supply line to the furnace ?........If
this furnace will be gas, it is considered an appliance [ see Ch. 2 -
Definitions in the 2015 IMC ]........Also, Article 400.7, No. 8 allows
appliances to have the cord & plug as a means of disconnect, "IF"
the cord & plug assembly are rated to meet manufacturer'
requirements and the location of the appliance [ i.e. - higher heat
locations require a derating of the cord & plug assembly conductors ].

Option # 1: Have your Contractor provide you a [ full & legible ]
copy of the appliance manufacturer' installation manual.
Option # 2: Get the brand & model number of the furnace [ read
as "appliance" ], and look it up on the internet to verify for
yourself.

Until these questions can be fully answered, do not approve or
disapprove the install........Simply inform the Contractor that you
are researching the appliance to ensure a safe & compliant install.

@ ~ @
 
That was the call I made. It is a gray area so to speak but it comes down to Manufacturers specs and I know it calls for hard wire.
 
north star said:
@ ~ @

DMartin,

Are you saying that they will have a gas Water Heater and a [ fully ]
electric furnace, or is there a gas supply line to the furnace ?........If
this furnace will be gas, it is considered an appliance [ see Ch. 2 -
Definitions in the 2015 IMC ]........Also, Article 400.7, No. 8 allows
appliances to have the cord & plug as a means of disconnect, "IF"
the cord & plug assembly are rated to meet manufacturer'
requirements and the location of the appliance [ i.e. - higher heat
locations require a derating of the cord & plug assembly conductors ].

Option # 1: Have your Contractor provide you a [ full & legible ]
copy of the appliance manufacturer' installation manual.
Option # 2: Get the brand & model number of the furnace [ read
as "appliance" ], and look it up on the internet to verify for
yourself.

Until these questions can be fully answered, do not approve or
disapprove the install........Simply inform the Contractor that you
are researching the appliance to ensure a safe & compliant install.

@ ~ @
Click to expand...
I told him if he could provide me with the Manufacturers specs I could possibly approve it but he has not responded so I will see if he fixes it. or response with some specs but I am pretty sure it calls for hard wire. The furnace is electric but the WH is going to be gas.
 
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