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- Thread starter Young Frankenstein
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Brew12
Electrical Gru
Since you ran 12/3, use one as the hot, one as the neutral, and one as the ground. Keep the circuits completely separate imo.
jrlg
Active Member
ok now I'm confused, kind of getting a 50/50 on this project. using a 12/3 wire, which has a red, black, white and bare wire, @fermentedhiker are you saying using the two hots and shared neutral is bad? or having the breakers tied is bad?
Brew12
Electrical Gru
I would say that both are bad. You don't want shared neutral or tied breakers on 120v system imo.
I'm saying the idea of sharing a neutral is bad. If you share a neutral you have to tie the breakers together, which I don't think is even allowed by code any longer. When you share a neutral in these multiwire ckts, you are linking two 120V ckts with a common neutral. Essentially you are placing the loads on each ckt in series with each other. It acts like a bizarre hybrid 220v ckt which sometimes cancels out current flow between the phases and sometimes uses the neutral depending on how unbalanced the load is between the two circuits. Just not a good idea in my opinion. Two runs of 12/2 wouldn't cost you much more than one 12/3 so I don't see how the small cost savings can be worth the potential headaches.
jrlg
Active Member
@fermentedhiker, @Brew12, thanks for the advice I think I will drop running the second line and use one 20 amp then, two lines was over kill because I have an existing 15amp outlet in the wall that I can convert use, I just didn't want to over load one circuit.
Someone wired a circuit in my house like this. I found a box with a 12/3 romex in it in the utility/storage room and traced it back to the breaker box to see they tied the red to one 1P breaker and the black to another 1P breaker. Scratched my head on that one since my house was built in 2000...fortunately only one hot was being used, but now that I'm reading this thread I might have to take another look and see if I pulled a noonan and used that 2nd hot for a new circuit down there....
jrlg
Active Member
the interesting thing about thinking of this12/3 two line set up, I got the idea from a quote of a major electrical company that was going to install it for me that way for an extra 150 dollars.….
They were going to charge you extra to do something that used less material? I think these types of circuits had a specific purpose in situations where the loads were almost identical, but I can't see using them on two circuits with essentially random loads would make sense. To be clear I've not run across a single instance of a licensed electrician installing one in a residential application. Commercial stuff is outside of my wheelhouse though.
Brew12
Electrical Gru
You see shared neutrals on 277V lighting systems fairly regularly. It is a horrible practice. It works fine as long as the current of both hots together is within the rating of the neutral. You don't typically see it in non lighting circuits because it is easy to overload the neutral wire. It also makes troubleshooting ground faults a pain.
But, functionally, it works. All of your neutrals are tied together and to ground in your electrical panel so from a theory perspective, it shouldn't cause any issues doing it that way. That doesn't make it a good idea.
Double checked and I was right you can join separate breakers anymore. So you would have to use a double pole Arc fault or a conventional double pole with two arc fault receptacles(one for each circuit). Drives the cost up quite a bit I would guess. The real danger I see with these especially with unbalance load is if the neutral goes open between the panel and the first outlets where the neutral is split off would wreak havoc with the equipment as the circuits would still be trying to run as a path is still available across them.
jrlg
Active Member
I started something here, as I said the idea for the 2 lines with the 12/3 came from a quote from a licensed major electric company;
"This is an estimate to run a dedicated 20 amp circuit from the main electrical panel to the opposite side of the house for the aquariums Will actually be a 12 three wire so customer can have two dedicated circuits at the aquarium in a two gang junction box There is no attic there will be dry walled cuts to get the wire up into the ceiling and pushed across the house to the new location customer is responsible for all the drywall repairs or we have a drywall division and they can come out and give you a quote to repair all drywall"
I am taking your advice and not running the 12/3wire for two circuits , but overall the quote left me with a bad impression of the company, he called and quoted an outrageous price without looking at the scope of work over the phone, (I took the day off of work to be at the house for the appointment which was the time he called)
I am not a licensed electrician but I do a lot of DIY around the house, and I like to do things safe and correct the first time and I use experience, mine and others and common sense when doing anything. To add to the situation I am only setting up a 200gal tank so a 15amp shared outlet that is already in the room and the dedicated 20amp will be enough power for the tank, and will give me the piece of mind that I wont burn down the house or blow the circuits and crash the tank, @fermentedhiker and @Brew12 thanks for your input.
"This is an estimate to run a dedicated 20 amp circuit from the main electrical panel to the opposite side of the house for the aquariums Will actually be a 12 three wire so customer can have two dedicated circuits at the aquarium in a two gang junction box There is no attic there will be dry walled cuts to get the wire up into the ceiling and pushed across the house to the new location customer is responsible for all the drywall repairs or we have a drywall division and they can come out and give you a quote to repair all drywall"
I am taking your advice and not running the 12/3wire for two circuits , but overall the quote left me with a bad impression of the company, he called and quoted an outrageous price without looking at the scope of work over the phone, (I took the day off of work to be at the house for the appointment which was the time he called)
I am not a licensed electrician but I do a lot of DIY around the house, and I like to do things safe and correct the first time and I use experience, mine and others and common sense when doing anything. To add to the situation I am only setting up a 200gal tank so a 15amp shared outlet that is already in the room and the dedicated 20amp will be enough power for the tank, and will give me the piece of mind that I wont burn down the house or blow the circuits and crash the tank, @fermentedhiker and @Brew12 thanks for your input.
jrlg
Active Member
the extra price was going from 12/2 to 12/3
looking at how the neutrals are all tied together with the grounds was why I thought the shared neutral will be ok in the first place, but the current coming back on the one neutral not being even could be an issue also during a google search I saw a warning about sharing a neutral on a gfci outlet would not work because it would cause a trip detecting the different current
Brew12
Electrical Gru
A shared neutral, if done correctly, will still work with GFCI circuits.
Personally, I would try and find a different company to use. Unless there is something odd going on in your house, there should be no drywall damage to be repaired. If there is a challenge with the wire pull that requires drywall damage they should be able to explain exactly what is going to be done before they start.
I also don't trust that they know their stuff from an electrical point of view. 12AWG is used in 20A circuits because of it's current ratings. A single wire is rated to 34 amps. If you do a 2 or 3 conductor cable, the rating is 20 amps. Since the neutral carries the load current from both hot legs you would be limited to a total of 20A on both circuits combined. Which leads to another problem.... this would be against the National Electric Code unless you supplied each circuit with a 10A breaker.
I know it's a pain, but I recommend looking elsewhere. It could be you don't have a good option when it comes to electrical contractors near you, but I hope you can find better.
NewbyREEF
Active Member
Can i join neutral like this ? It's going to an 8 channel relay that's connected to a Feef-Pi
Erica-Renee
Valuable Member
Can i join neutral like this ? It's going to an 8 channel relay that's connected to a Feef-Pi
Yes ..
NewbyREEF
Active Member
thank you you rock!
Hi all,
I recently just went to switch my substrate in my tank and as soon as I unplugged a powerhead... my outlets tripped. It’s weird because my breaker downstairs isn’t tripped. It has a gfci outlet set up but when I press reset a light pops up red and nothing else happens. This is kinda a horrible time to have all this happen considering I was in the process of removing everything. Any advice will be greatly appreciated. Do I need to replace the outlet? What’s also weird is that I have power to half my room. The even weirder thing is that the outlet on the same wall ( not on the gfci outlet switch thing) is also off. Any ideas?
@Brew12
I recently just went to switch my substrate in my tank and as soon as I unplugged a powerhead... my outlets tripped. It’s weird because my breaker downstairs isn’t tripped. It has a gfci outlet set up but when I press reset a light pops up red and nothing else happens. This is kinda a horrible time to have all this happen considering I was in the process of removing everything. Any advice will be greatly appreciated. Do I need to replace the outlet? What’s also weird is that I have power to half my room. The even weirder thing is that the outlet on the same wall ( not on the gfci outlet switch thing) is also off. Any ideas?
@Brew12
First it sounds like you have a pump or heater thats going bad, First unplug everything then try to reset Gfci if that works then, Unplug each one until the problem goes away. If that doesn't do the trick then update this thread.
BTW @Brew12 has a BIG thread on Grounding your tank and the GFCI
BTW @Brew12 has a BIG thread on Grounding your tank and the GFCI
Usually newer GFCI receptacles have the light on when it's working. So are you saying that you cannot reset the GFCI?
The other receptacle is undoubtedly downstream from the GFCI (hence it is protected by it)
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