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#90273 11/11/04 01:57 PM
Joined: Feb 2004
Posts: 41
rknikko Offline OP
1)What is the maximum length can be exposed for BX and Romex wires?
2)The code specify a need for receptacle within 25ft of a Heating or Cooling unit. What if the unit is outside of the house and the receptacle is inside of the house, but it's still within 25ft? Would that be OK?

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#90274 11/11/04 03:43 PM
Joined: Jan 2004
Posts: 1,507
My answer to Q. 1 There is no limit to the length of exposed "Romex" cable or "BX" but there may be some issue with environment or physical protection. 334.15 for NM (Romex) and 320.15 for Armored Cable (BX) Q. #2- 210.63 is silent about the indoor or outdoor issue. It only says that it must be accessible and on the same level as the A/C unit.

George Little
#90275 11/11/04 05:47 PM
Joined: Feb 2004
Posts: 41
rknikko Offline OP
The BX cannot be exposed for more than 3ft I believe. When I say expose, I mean it will not be hidden in the wall. As for the attic, I believe this rule do not apply, but for finish wall, this is another case.

#90276 11/11/04 06:13 PM
Joined: Dec 2003
Posts: 886
Don't know where you are getting the idea the BX, which is type AC now, cannot be run exposed. You can run it as long as you want subject to 320.15.

As to your question about the service receptacle, the code only says that it must be within 25 feet. I would not consider a receptacle in another space or inside the house to meet that requirement however.


#90277 11/11/04 08:36 PM
Joined: Nov 2000
Posts: 2,148
I don't think that a service receptacle inside for equipment outside would be in compliance with this part of the rule.
The receptacle shall be located on the same level and within 7.5 m (25 ft) of the heating, air-conditioning, and refrigeration equipment.
In most buildings the inside floor is at a higher level than the outside grade.

#90278 11/11/04 09:19 PM
Joined: Dec 2003
Posts: 886
In most buildings the inside floor is at a higher level than the outside grade.

Well that may be stretching it a bit [Linked Image] but I think the intent is to have the receptacle available for easy access by a serviceman and that's why the code requires one to be installed. If you had to run an extension cord through doors or windows we would be back to the days when the receptacle wasn't required.


#90279 11/11/04 09:53 PM
Joined: Jun 2003
Posts: 1,143
1) Many local town are adopting "exposed run" restriction, but that's a local Code issue, not one found in the NEC, as long as support requirements are met. My town started that a few years ago, limiting exposed runs of AC, MC & Greenfield to 24" from penetrations (except for motor and lighting whips). Most of the IL Lake Shore has already outlawed NM, so that's moot for us.

2) I've always installed one within L.O.S. of the HVAC in the basement - usually a lot less than 25'.

I've always heard the "25'" rule applied to roof mounted HVAC / mechanical stuff - so they wouldn't have to run extension cords from inside the building. (or to sign receptacles with adaptors)

#90280 11/12/04 01:42 AM
Joined: May 2003
Posts: 2,876
e57 Offline
What if the HVAC guy doesn't have access to the interior?

Mark Heller
"Well - I oughta....." -Jackie Gleason
#90281 11/12/04 08:44 AM
Joined: Oct 2004
Posts: 265
I would always place the outlet in line of sight or next to the equipment.

I think it was in the code update notes that they were trying to prevent A/C guys from taking a leg of the A/C power and hooking up to the ground to provide power for their cords.

#90282 11/13/04 01:34 AM
Joined: Apr 2002
Posts: 2,527
Aside — There are odd little special-application fused-receptacle/disconnect switches like that at:

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