Electrical Help?

[oldsaltman]

I have been running my complete setup off one dedicated 20 amp ground fault breaker with a 20 ground fault receptacle. I have not had any problems YET. I checked the total amp draw and it is about 15 with everything on. I decided to add a new line for the aquarium this week. I plan to use a 40amp std double poll breaker and 8/3 w/ground wire. I am going to split the two hot wires into two receptacles each. I am going to use (4) ground fault receptacles. Do any of you electricians see a problem with this? I bought the stuff I just haven’t done it yet.

 

[marm64]

There is really no reaso for you to run 8/3 wire with a 40A double breaker. What I did was run 12/3 w/ground and a double 20A breaker.

You should not hook up a 20A outlet to a 40A breaker. You only need a 20A breaker since you are only hooking up to a 20A outlet. You can use the 8/3 and hook up to a 20A breaker but it is much easier to work with 12/3.

 

[oldsaltman]

If I am installing two 20a ground fault outlets per leg of the 8/3 wire why would I not want to use a 40a breaker? Would I not be cutting back the "usefull" amps of each outlet to 10a each if i use the 20a breaker?

 

[revance]

You should NEVER run a 20A receptacle on a 40A breaker because then there is nothing protecting that receptacle from being overloaded and catching fire.

Receptacles do NOT limit the current... if it is rated at 20A and you have it on a 40A breaker, it is possible for you to run 40A through that receptacle and have it catch fire.

 

[46bfinGA]

<a href=showthread.php?s=&postid=8405794#post8405794 target=_blank>Originally posted</a> by SA057
If I am installing two 20a ground fault outlets per leg of the 8/3 wire why would I not want to use a 40a breaker? Would I not be cutting back the "usefull" amps of each outlet to 10a each if i use the 20a breaker?

you do not want to use a 40 amp two pole breaker.the 8/3 is really too large for what you need unless you are 4-500 feet away from the panel.
what you are going to need is two seperate 20 amp single pole breakers.that way each circuit is protected up to 20 amps and nothing more.if you use a 40 amp breaker on a 20 amp outlet the outlet will burn up before the breaker will trip.(not good)
you can put as many outlets as you want on each leg as long as your total current draw is less then 80% of 20amps.hope that helps.
if its possible you can return the wire you bought and get some 12/3 or 10/3 if that makes you feel more comfortable.the 8 awg gauge wire is going to be very difficult to install on a 20 amp outlet,unless you use a wire nut and attach a smaller wire.
return two of the ground fault receptacles,you will not need four.you can wire the receptacles in series off the ground fault.just follow the directions that come with the ground fault so that the receptacles that are after it are protected as well.

 

[Cuervo]

You could do a 40a breaker to a subpanel in your fish area. Then put a pair of 20a breakers in the subpanel, each with it's own circuit.

 

[revance]

He could use a subpanel, but if he is having difficulty understanding why you shouldn't run 2x20A receptacles on a 40A line, he probably shouldn't be installing subpanels (or extra circuits for that matter).

With all due respect... please hire an electrician.

 

[46bfinGA]

<a href=showthread.php?s=&postid=8405997#post8405997 target=_blank>Originally posted</a> by Cuervo
You could do a 40a breaker to a subpanel in your fish area. Then put a pair of 20a breakers in the subpanel, each with it's own circuit.

good idea if you are planning on upgrading at some point,but if not then its really just wasted money.

 

[oldsaltman]

<a href=showthread.php?s=&postid=8405997#post8405997 target=_blank>Originally posted</a> by Cuervo
You could do a 40a breaker to a subpanel in your fish area. Then put a pair of 20a breakers in the subpanel, each with it's own circuit.

This is what I wanted to do but I can't find a small sub box for just two breakers!

 

[revance]

He is wanting 4 x 20A receptacles... so a subpanel might not be a bad idea depending on how far away the tank is from the breaker box and how many slots he has in his box.

He could have an electrician run an 80A breaker to a subpanel by the tank that has 4 20A breakers. Put a single receptacle on each circuit.

 

[46bfinGA]

<a href=showthread.php?s=&postid=8406063#post8406063 target=_blank>Originally posted</a> by SA057
This is what I wanted to do but I can't find a small sub box for just two breakers!

they sell sub panels at home depot.you can just use two breakers and have spares for later on down the line.

 

[Paul B]

All of these answers are correct. Of course it would work fine but it is also a code violation. As was said a 20 amp GFCI recepticle is not rated for 40 amps. Even though you are not plugging in 40 amps to it, it is a violation. A 20 amp receptacle has internal copper bars rated for 20 amps and they would melt if for instance your powerhead shorted and drew 30 or 40 amps which it could do with a 40 amp breaker. Two panel circuit breakers are very common. Go to an electrical supplier not Home Depot.
Use a 40 amp sub panel and connect two 20 amp breakers but even that is overkill. Just use two 20 amp seperate circuits with #12 wire.
I myself have a 100 gallon reef on a 20 amp line for over 30 years and it is not even a dedicated circuit. I have never tripped that circuit and there is no reason it should ever trip unless I drop a light in the water.
Paul

 

[oldsaltman]

Does a 20amp ground fault outlet not provide the same protection as a 20amp circuit breaker? I am getting from the responses that it does not. If it does not provide 20amp protection then I understand the difference. With all due respect I don't think I need an electrician to pull a wire 20feet and connect it to a breaker and an outlet. I ask the original question to get expert advise on my thoughts to add circuits.

 

[oldsaltman]

Paul B, thanks for your reply, I just wanted to make sure my wire was enough for any future upgrades and handle my current problems.

 

[revance]

NO receptacles (even GFCI) are not circuit breakers! They will not trip if you pull more than their rated current, they will simply catch fire.

Believe it or not, there IS more to it than just running a wire and connecting it on the end (at least if you are concerned about code). You have to make sure the cable isn't bent improperly during installation. You have to ensure the wire properly supported, you have to make sure it enters the panel properly and is secured where it enters. This is probably not an issue in a private residence, but you need to know if an area of the wall is a plenum.

All I am saying is that with the amount of electrical knowledge you currently have you might be better off getting a professional or at least doing a bit more reading on the subject. At least go to the library and pick up a national electrical code book. An aquarium forum isn't a good primary resource for this (no offense to all the perfectly qualified people here).

 

[Paul B]

SA057 a GFCI is not a circuit breaker and it will not trip off with an overload. It would probably melt first. A GFCI only trips on a ground fault which is different than an overload.
I am not an expert but I have been an Electrical construction foreman for almost 40 years in Manhatten.
Paul

 

[oldsaltman]

OK, I am going to add a sub panel with two 20a GFBs. I guess I should have just planned for that to start with.
Thanks

 

[revance]

Why are you using a GFB if you are using GFCI receptacles? It really isn't necessary. Granted the ground fault breakers have better response than receptacles, but I don't think it is worth the extra cost (they are really expensive). This isn't in a bedroom is it? If so, then you want to use an AFCI breaker. Well... maybe not "want", but it is code.

 

[oldsaltman]

I didn't buy the GFB to start with because they are costly. If I don'd need them then I will just use the 40a in my main panel and two std 20a in the sub box with all GFCI outlets.

 

[BeanAnimal]

<a href=showthread.php?s=&postid=8405582#post8405582 target=_blank>Originally posted</a> by marm64
There is really no reaso for you to run 8/3 wire with a 40A double breaker. What I did was run 12/3 w/ground and a double 20A breaker.

You should not hook up a 20A outlet to a 40A breaker. You only need a 20A breaker since you are only hooking up to a 20A outlet. You can use the 8/3 and hook up to a 20A breaker but it is much easier to work with 12/3.

The NEC does not forbid you from hooking up 15A or 20A receps to higher rated breakers. The wire is the limiting size for the breaker. The plug configuration is the limiting size for what can be plugged into each receptacle.

His plan would be fine but has some drawbacks. Firstly it is obvious that the overcurrent protection is much more than would be intended for most of the devices on each branch. Furthermore, a faulting device would trip ALL of the devices. There are other issues... but needless to say this is not the best approach.... (as some of you have already covered).

Bean