15 amp GFCI in 20 amp circuit.

Reply

  #1  
Old 05-08-05, 03:42 PM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
15 amp GFCI in 20 amp circuit.

I'm adding a room in an unfinished area of the basement. The 20 amp circuit currently has only one receptcle. I'm going to tap off of that recepticle to go to the new room. Would it be ok to put a 15 amp GFCI in that receptcle?

Also, am I I OK putting 14 ga wire in?
 
Sponsored Links
  #2  
Old 05-08-05, 04:42 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
It is okay to put a 15-amp GFCI on a 20-amp circuit. It is definitely not okay to put any 14-gauge wire on a circuit protected by a 20-amp breaker. You must use 12-gauge wire.

Having answered your direct questions, there are dozens of ways that this might violate code anyway. Specifically I'd like to know everything that the existing 20-amp circuit currently serves. Often it is serving bathroom receptacles upstairs. If so, it would make it a code violation to add your bedroom receptaclest to it. There are other possible problems too. Please provide more details. Are you 100% sure that the one receptacle is the only thing on the circuit?
 
  #3  
Old 05-09-05, 12:36 AM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
Thanks for the input. I went around and double checked. There are no other loads on this circuit.

I can see from your comment that I'll need to put a 15 amp breaker there. (I've already run the 14 ga wire.)

The existing outlet has the power box to the phone system plugged into it and the water softener. I'm pretty sure they each draw very low amperage. The phone box, has a battery backup that lasts for almost a day. That means that it isn't drawing much. The water softener is powered by a 24v wall transformer. The cord is tiny. I've left the breaker off for a day more than once, and no other outlets are affected.

The way I have the wire run now is;

from the existing outlet to the first new outlet, from that outlet, to the smoke alarm. Due to the layout, the smoke alarm will be a junction to the other three outlets and to the light switch. The light switch will switch two 75w recessed lights. Two of the outlets that are branched off of the smoke alarm box are low profile, steel boxed because they are along the wall which is concrete. The furring strips are actually 2x4s laid flat on the concrete and nailed with concrete nails. Since they are laid flat, the box is only 1.25". This way, I only have a wire going in. I don't have one going out.

When I get this to the point I beleive it is up to code, I'll have the city inspector come in to inspect it. Hopefully, with your input, it'll be right the first time.

Thanks again
 
  #4  
Old 05-09-05, 12:48 PM
Skapare's Avatar
Member
Join Date: Jun 2004
Location: USA
Posts: 198
Originally Posted by gregp1962
Thanks for the input. I went around and double checked. There are no other loads on this circuit.

I can see from your comment that I'll need to put a 15 amp breaker there. (I've already run the 14 ga wire.)

The existing outlet has the power box to the phone system plugged into it and the water softener. I'm pretty sure they each draw very low amperage. The phone box, has a battery backup that lasts for almost a day. That means that it isn't drawing much. The water softener is powered by a 24v wall transformer. The cord is tiny. I've left the breaker off for a day more than once, and no other outlets are affected.
If that existing receptacle is a 20-amp type (the larger slot will have a side slot forming a sideways "T") then you will need to downgrade it to a 15-amp type to go with the 15 amp breaker.
 
  #5  
Old 05-09-05, 01:30 PM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
Skaspare, Thanks. That should be easy enough since that is where I need to put the new GFCI. (BTW, yes, it is a 20 amp outlet as you describe)

SO, I can either rerun 12 ga wire and keep the same 20 amp breaker and add a 15 or 20 amp GFCI at the point where the existing outlet is, or;

Put in a 15 amp breaker in place of the 20 amp one and replace the existing outlet with a 15 amp GFCI, right?

I'm thinking that the load is going to be so low on this circuit that the 12 ga and 20 amp breaker is overkill. I really don't want to throw out the 14 ga wire I have already run. What do you all think?

John, do you see any issues with my description of the wiring scheme described in the 3rd post?
 
  #6  
Old 05-09-05, 01:39 PM
Skapare's Avatar
Member
Join Date: Jun 2004
Location: USA
Posts: 198
Either should be OK. I think your best solution is to just use a 15-amp breaker and 15-amp GFCI if the wire is already covered.

Note that the inverse is allowed; you can use 15-amp receptacles on 20-amp circuits (provided it's not a single dedicated outlet). But the AWG 14 wire requires the circuit be protected at 15 amps.

You might want to permanently attach a note on the inside door of the panel that this circuit has 14 gauge wire installed so someone in the future does not assume that because there is 12 gauge coming in to the panel that the whole circuit is 12 gauge.
 
  #7  
Old 05-09-05, 02:34 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Although not specifically prohibited by the NEC, some inspectors don't like to see you mix #14 and #12 on the same circuit, especially if there is #12 at the panel. So if you want to maximize your chances of passing on the first try, I'd replace your #14 with #12. Besides, putting a 15-amp breaker on this circuit is like putting training wheels on your muscle car.

And I also don't really like to see people using furring strips to finish their basement, even if they are 2x4s on the side. A regular 2x4 wall is a much nicer treatment, and you'll never miss the extra couple of inches. The standard stud wall will be more straight, more plumb, more resistant to moisture problems, easier to rough in, easier to insulate, and easier to finish. Foundation walls are notoriously crooked, something you may not notice much until you get the walls painted. (Forgive the aside--this isn't really an electrical issue.)

Despite my reservations expressed above, your plan is sound.
 
  #8  
Old 05-09-05, 04:42 PM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
Thanks guys. What I'm going to do is keep the 14 ga wire, replace the breaker with a 15 amp breaker and replace the existing 20 amp outlet with a 15 amp GFCI. Then, the only possible issue could be mixing 12 with 14. But, it seems that having the 12 from the box, then 14 ga after the GFCI is safer than having 14 ga all through the circuit.

I'll use a string line to make the furring strips straight. Moisture is never a problem in this particular basement.

I'll let you know how it turns out.
 
  #9  
Old 05-09-05, 06:26 PM
Speedy Petey's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Nov 2003
Posts: 2,455
Originally Posted by gregp1962
But, it seems that having the 12 from the box, then 14 ga after the GFCI is safer than having 14 ga all through the circuit.
Just a comment.
This statement is completely false. In fact it is less safe, for the reason John stated.
 
  #10  
Old 05-09-05, 07:14 PM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
Originally Posted by Speedy Petey
Just a comment.
This statement is completely false. In fact it is less safe, for the reason John stated.

I can't find what John said about it being less safe.
 
  #11  
Old 05-09-05, 07:51 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
The unsafe part is that in the future someone may see 12 gage wire at the panel, think the entire circuit is 12 gage, and replace the breaker with a 20 amp breaker.

Please, if you leave the mixed wire gages, make an explicit note in the panel as to why there is a 15 amp breaker on 12 gage wire.
 
  #12  
Old 05-09-05, 08:05 PM
Speedy Petey's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Nov 2003
Posts: 2,455
That is what I was referring to. I guess it was more implied than stated.
 
  #13  
Old 05-10-05, 01:50 AM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
OK Speedy, I see your point now.

I was looking at connecting these wires and realized that there is one spot I'm not sure about. The point where I have the power coming in to the box for the smoke detector and I'll have it split from there to two outlets and the light switch. That's putting alot of wires together in one spot what is the best way to do that?
 
  #14  
Old 05-10-05, 07:41 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
The best way to put a lot of wires together in one box is to not do it at all. Usually a good cable routing design will keep the number of cables in any one box down to a small number. But if you didn't do that, you'll need a big box and big wire nuts.
 
  #15  
Old 05-10-05, 08:36 AM
Member
Thread Starter
Join Date: Mar 2005
Posts: 49
There's no terminal block that could be used to connect them? That would seem cleaner that changing the routing of the cables. To me, it seems that a hub type system would be better than a big, spread out web.
 
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
Display Modes