Any electricians out there?

[Ilsimen]

First off, let me just say that though I am not an electrician, I DID attend two years of tech college to become an electrician. Unfortunately, since this was 20 years ago and my life went a different direction after school, I have forgotten most of what I learned as far as keeping up to Code and what not. I am fully capable of doing the work, I'm just hoping what I am thinking about doing will be safe and want to check with people that know more than I do.

Here's my situation. I want to run a few dedicated circuits for my new tank build. Unfortunately, my breaker box is full, but as luck would have it, one of the circuits is a 100 amp breaker that feeds an auxiliary panel. This panel holds a 30 amp for the water heater and a 30 amp for the AC, and it has room for up to 4 more 15 amp circuits.

My question is, am I allowed to used all 4 available slots for 15 amp circuits knowing that under normal conditions, all of the equipment want draw the max current they are rated for, or am I limited by the 100 amp breaker to keep the sum of the circuits in the sub panel less than/equal to 100 amps. And if that's the case, can I swap out the 100 amp feeding the sub panel for a larger breaker understanding that I would have to increase gauge of wire feeding the panel (not a big deal since there is conduit running between the two panels.) 20 years ago I could have answered my own questions but having not thought about this stuff at all since school, I am drawing a blank. I'm hoping that even though this isn't technically reef related, that someone here will be able to help me.

Mods, if there is a better forum for this question, feel free to move it.

[Aslmx]

Keep the 100 amp but use 20 amp breakers for your new ones with #12 wire. The breakers protect the wire so the 20 amps protect the branch circuits and the 100 amp will do the same for the sub panel. This information is in consideration that the rest of your set up is sized and installed to the code by the way.

[Ilsimen]

Ok if i make them 20 amp circuits, that will put 140 amps worth of circuits on a 100 amp breaker. Now I now the chances of all the circuits pulling their max rating at any one time are slim, I just want to make sure what I plan on doing is to code. I really wish I remembered what I learned in school.

[Aslmx]

What size is your main service?

[fermentedhiker]

As was mentioned the breaker size is to protect the wire. The total AMP value of the individual circuits isn't related to the main disconnect(or in this case the main for the sub panel). You can put either 20 or 15 amp breakers in the slots without issue. Just use the correct sized breaker for the wire you run. 20 AMP for #12 or 15 AMP for #14

[Cmoua]

Sounds that you got the gist of it, your breakers won't max out their current ratings or they'll trip to let you know. So long as you have room, you can add a few more circuits.

[Ilsimen]

Yeah, it's coming back to me now! Thanks for the help!

[Utwo229]

Yes ok with code as long as everything is wired correctly.. If the load goes over 100 amps then it'll trip the breaker.. Then you'll have to solve that problem another way, all in all still safe.

[alton]

Just to add to what others have said you will need to use arc fault breakers per the 2014 code. And for safety sake GFCI receptacles. Use insulated staples for your romex installation.

[SGT_York]

You won't need Arc Falt as this is not a bedroom or living area. Secondly your pumps will trip it during startup if you do. GFCI outlets are a must.

[Paul B]

Aslmx is correct.
(Master electrician 40 years)

[alton]

Originally Posted by SGT_York

You won't need Arc Falt as this is not a bedroom or living area. Secondly your pumps will trip it during startup if you do. GFCI outlets are a must.

2014 NEC Article 210.12A
All 120v 15 and 20 amp branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas must follow 210.12 A 1 through 6 for AFCI protection
I have a newer style GE AFCI breaker that I use for my test and I have not had a motor or ballast trip it yet. The old ones tripped all the time.

[SGT_York]

Glad to hear the new ones work, I'm still on 2008 NEC so happy me!

[alton]

Originally Posted by SGT_York

Glad to hear the new ones work, I'm still on 2008 NEC so happy me!

The way it is going to make sure everyone is safe we might as well change from 120v to 48v. I am seeing the changes people want for 2017 and it is amazing. I can buy a 12 circuit panel for $12.50, but to fill it up with breakers will cost $420! Oh yea since they now make AFCI receptacles if you add an additional plug you know have to install one of those a head of it to protect the Romex/new receptacle, there not cheap either

[boban070]

Does anyone have a link to your American electrical regs? I would be interested to compare it to our Australian version.
We don't use any form of arc detection here. Circuit breakers are a must, as are gfci(we call them rcd's) for us only.

[alton]

More countries are adopting the NEC, it maybe there before you know it? My loose leaf book cost me $100 a year ago.

[Utwo229]

We are still on 2008 here in Florida. Rumor has it that they may skip 2014 too. In the future you'll see a lot of new homes with the absolute minimum number of breakers to pass inspection.