Adding outlet to furnace that has flex conduit?

Reply

  #1  
Old 12-08-16, 07:37 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Adding outlet to furnace that has flex conduit?

I purchased an aprilaire 700 humidifier, but i don't have a convenient outlet to plug into. So I want to add one but not sure how. I was told nec 400.7. Prohibits adding outlet to flexible conduit. Then what is the best way to add an outlet to the dedicated furnace electric?

There is an overhead ceiling light box above which carries dedicated power for: light itself, ejector, furnace, and the doorbell transformer taps into it. The light, ejector, and furnace are all on its own breaker. Not sure what doorbell is tapping into. The furnace service switch is across from the unit. The red wire comes through light box and goes to switch, comes back with orange wire and heads to furnace through flex conduit.

Also, is gfci outlet needed in this area? If so does anything special need to be done for the gfci outlet?

Thank you.

Picture of furnace setup:
https://imageshack.us/i/pn36DL2sj
 
Sponsored Links
  #2  
Old 12-08-16, 07:57 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
You can mount a 4" steel square junction box to the side of the furnace and run the flex conduit to a proper fitting on that box. I'd actually mount it on the KO hole where the conduit currently enters the furnace and run a close nipple from the box into the furnace. You can then install your GFCI receptacle in the box with a raised cover and run wires directly into the furnace.

Note that this would not be a general-purpose outlet per code as a dedicated circuit is required for the furnace, but it can legally power accessory equipment like the humidifier.
 
  #3  
Old 12-08-16, 08:25 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Okay, to make sure I am understanding. Disconnect the flex conduit where it is currently at (leading into furnace). Then connect it to a junction box, and mount the juntion box to the furnace right over the hole the current flex conduit is running to...

Then branch the accessory outlet off that box?

How would the wiring be for the outlet and furnace? I would think that if the gfi trips, it should only trip the humidifier. So would wiring first fo to gfi and then branch off that to furnace (assuming there is a constant power feed option even if gfi trips). If not, is gfi outlet neccessary here, if so, how would i get constant power to furnace in event gfi trips.

I also have a transformer for the humidifier that will need to tie into this junction box. Can i twist tge transformer hot wire with the hot wire going into outlet? Thanks!
 
  #4  
Old 12-08-16, 08:44 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Correct on all points. The furnace should not be on the load side of the GFCI, feed constant power to both; use only the "line" terminals and the GFCI receptacle will only affect itself if it trips. You can branch off to another box for the accessory outlet or just install it in the box right on the side of the furnace.
 
  #5  
Old 12-08-16, 08:56 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Thanks ibpooks!

I am still unclear on how it would be installed in the box on the side of furnace, if i didnt branch to new box. Do you have a picture?

Also, how would i connect the transformer to all of this? And can i just mount the transformer on top of the junction box or should i mount it inside the furnace somewhere?

Thank you for your patience. I just want to make sure I am doing this safely.
 
  #6  
Old 12-08-16, 10:06 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
Instead of a GFI receptacle...... use a dedicated purpose single receptacle.
You won't need the transformer if you are using the automatic humidistat.

Name:  single recp.jpg
Views: 646
Size:  14.7 KB

Name:  700_furnace power.jpg
Views: 898
Size:  29.1 KB
 
  #7  
Old 12-08-16, 11:43 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Okay thanks pjmax. I am just worried about everything being up to code. So the box in the picture you show is basically what ibpooks is talking about. And I would lead the flex conduit into that, which that box is attached to furnace with wires leading into furnace from back of it.

If I do it your way and not use transformer, the humidifier will still power on and run even if heater/furnace fan is not running, correct?
 
  #8  
Old 12-08-16, 08:24 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,980
Received 35 Votes on 30 Posts
Instead of a GFI receptacle...... use a dedicated purpose single receptacle.
You won't need the transformer if you are using the automatic humidistat.
Receptacles in an unfinished basement require GFI protection. The cover plate shown would require GFI protection by a breaker or a GFI device upstream.
 
  #9  
Old 12-09-16, 06:34 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Isn't that only for non fixed devices? The humidifier will be fixed equipment, kind of like how a fridge wouldn't require a gfci because it's a fixed unit.

This is based off my readings, I am by no means an expert.
 
  #10  
Old 12-09-16, 06:54 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
kind of like how a fridge wouldn't require a gfci because it's a fixed unit.
For hard wired usually but from my understanding that is old code for plugged in appliances and the exception has been removed. My best guess they figured anything could actually be plugged in not just equipment that is exempt.
 
  #11  
Old 12-09-16, 09:16 AM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Ah okay, well at any rate. It's better to be safe than sorry. I know these things can be sensitive, my new construction house has some that pop intermittently.. I was considering avoiding it just because of that. As long as the furnace will be pigged tailed on its own supply then if it does randomly pop, my rabbit in the basement won't freeze to death
 
  #12  
Old 12-09-16, 11:03 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
You could train the rabbit to reset the GFCI.
 

Last edited by ray2047; 12-09-16 at 11:58 AM.
  #13  
Old 12-09-16, 12:16 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
There is a borderline issue here. Now you'll install a GFI receptacle and have a place to plug something else in on the furnace circuit.

I use a single gang box with a switch and receptacle on all my installs. Just used it last month.
 
  #14  
Old 12-09-16, 12:44 PM
Member
Thread Starter
Join Date: Mar 2016
Location: USA
Posts: 105
Received 0 Votes on 0 Posts
Ray2047, haha, well since I can't get the fiancÚ or dog to listen to me, maybe I'll have better luck with the rabbit!

PJmax,

I was thinking something like this if I did do the gfci:

https://www.zoro.com/leviton-gfci-re...B&gclsrc=aw.ds


If I can find it at home depot.
 
  #15  
Old 12-09-16, 01:39 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
That would work. .
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: