Wiring new electrical for 300g tank

[Sethjamto]

I think I have about a hundred different threads going with different ideas I'm thinking of my new tank build, so here's another.

The wall I'm placing my 8ft 300g against has two outlets already, but they share a breaker with the rest of the room. I'd like to dedicate a breaker and a couple of outlets for just the tank. Running the wiring in the wall/attic to the breaker box is not problem. My question is, what size wire and breaker do ya'll recommend based on what I'm going to run for equipment below?

(2) Reeflo Darts (one return, one CL)
(1) Panworld 100 for skimmer
(1) Mag9 or 12 for skimmer
(2) Reefbreeder Photon 48 LED lights
800-1000watt heater, or (2) 500 watt heaters
JBJ ATO with small pump for topoff
Litermeter for dosing/waterchange
Controller
Maybe a max of two powerheads (depends on how much flow I can get out of the CL)
Various other smaller stuff.

Thanks!

[mcgyvr]

Breakers/Wiring should be sized according to any applicable electrical codes (National Electric Code) in your area.. You should always consult an electrician and use caution when working around electricity... Disclaimer done..

One might..
Add up the max wattage of all the equipment and divide by the AC voltage (120V for Alabama). That will give you the "amps". Pick a breaker size larger than the max continuous current rating. Pick the wire size based on the breaker rating and any applicable derating factors..

"typically" its 14AWG for 15A breakers and 12AWG for 20A breakers..
Make sure you get GFCI/AFCI breakers or include the outlets with that protection.
While typically not required by code the "smart" person ALWAYS incorporates GFCI protection as a minimum.

[adamgoldberg]

A 15A circuit theoretically can provide 15*120 = 1800 watts. This is theory, not actual. Would 1500 watts supply everything you need to supply? Typically this is 14/2 on a 15A breaker.

I just built a new house; I'm not sure I understand why, but the electrician wired all the GFCIs with 12/2 and a 15A breaker. 20A branch circuits are typically 12/2.

The cost and hassle difference for one circuit vs. two seems minor. If I were you, I'd put two 20A GFCI circuits, each using 12/2.

I am not an electrician. *** do I know.

[Hodge1995]

I would go with 2 circuits on a 2 - 20 amp breaker with 2- 20 amp gfci. supply lines will need to be a 12-2 with ground. I have a 300 and this is what I have.

[rfgonzo]

As said before 14-2 for 15amp and 12-2 for 20amp. I have a question for you, What skimmer are you going to run on a 300 gal tank with a mag 9 or mag 12?

[sleepydoc]

+1 on running 2 - 20 amp circuits. The difference in cost of the wire is minimal, the work is the same and you'll have plenty of head-room.

Depending on where the outlets are located, I would probably go with GFCI outlets over GFCI breakers. That way if one trips, it's easier to reset it near the tank rather than running to the service panel. NEC actually requires AFI breakers for living areas anyway.

[Sethjamto]

As said before 14-2 for 15amp and 12-2 for 20amp. I have a question for you, What skimmer are you going to run on a 300 gal tank with a mag 9 or mag 12?

Its the MRC MR4 rated for up to 900 gallons. I'm picking it up used from the previous owner of the 300g tank I bought. He said if I remember correctly, that he ran the skimmer with a Panworld pump AND a Mag pump. It made sense at the time he showed me, but now I can't remember the reason of the second pump. I "think" one is a circulation pump, and the other provides the air for the bubbles or something.....

http://www.aquacave.com/My-Reef-Creations-MRC-MR-4-Protein-Skimmer-P3800.aspx

[Sethjamto]

I agree with the (2) 20amp breakers on a 12/2 and will probably go with that.

[viggen]

I ran two 20a services for my 10ft tank plus have the old outlets in the wall.

W/o a doubt run two new services to the tank and split up the equipment between the. Two services. So if one circuit trips the other heater and pump are still running.

[billdogg]

Like everyone else has said - 2 x 20A breakers, with several duplex GFCI's per line. That's what I did for my 120 - and I could have installed another gangbox or two just to have the plugs available. Spring for the weather resistant outlets also - salt spray has a way of finding the worst possible places to end up.

[sfsuphysics]

I would go with 12/3 wire, and share the neutral just so I only had to run one cable, just make damn sure your hots are on opposite sides of the 120v.

If you plan on using some multi-outlet device like a DJ power strip, you could away with a single plug too, just pop out that little metal connector on the side of the outlet between the two terminals. Did something similar for the laundry room so I didn't need to add another plug.

[adamgoldberg]

I think you can do that, but elsewhere (on another forum) someone suggested that code may require use of a 240 breaker (that is, you're wiring a 240 circuit, but splitting the legs into two 120v branches at the back of your tank). There were some elec. code reasons for why. Also, on other forums, folks had trouble with GFCIs tripping when wired with a shared neutral.

IMHO, I can say with confidence that wiring two separate 20a circuits with 12/2 (all other things being equal) will be to code. I can't say that for two 20a circuits with shared neutral on 12/3. I am not an electrician, maybe sfsuphysics is.

[sfsuphysics]

I'm not an electrician either... at least a legal one :D However my entire house is wired with sets of shared neutrals with really old wiring. I do concede that it might not be up to code today, and in the large scale scheme of things is a major PITA to deal with if you want to swap panels out. That said I've never had an issue with GFCI's tripping on the house wire. As to the breaker issue, I believe you need a tie together the two 120 single pole breakers together, or use a double 120v, such that if you need to turn off the power it turns off both poles.

That said, for practicality 2 12/2 circuits isn't that much more difficult, just twice the holes you need to drill, twice the staples, twice the wire (although for some reason 12/3 is disproportionately more expensive than 12/2 based upon how many conductors you're getting, maybe the red sleeved copper is more expensive *shrug*).

That said, depending upon what the existing plugs that are "shared" are plugged into I might only run a single 20amp outlet. But if said shared load is with a TV, HT system, stereo then yeah all bets are off. Of course I run pumps that are quite a bit more energy friendly than what the OP is going to put on the system.

[adamgoldberg]

Re cost if you're doing it yourself... pay attention to the cost per foot of various length of wire. It might be cheaper to buy 250' of 12/2 than 100' of 12/3.

[sfsuphysics]

It is cheaper for 250' 12/2 vs 100' 12/3, 250' seems to be the cut off point where wire is as cheap as it gets (maybe marginally cheaper at 1000' but not many DIYers going to Home Depot are going to get that much wire)

[Redman88]

only need one GFCI per circuit, and it needs to be at the start, every outlet down stream from it will be GFCI protected. 12/2 over 14/2 is a better investment for the future. even if you use a 15amp CB in the panel.

[sleepydoc]

The cost of the circuit breakers is the same - if you pull 12 gauge wire, put a 20 amp breaker in; there's really no sense in down-rating the circuit.

Re: pulling 3 conductor wire and sharing the neutral, I've seen that in older houses, not in newer houses. I'm not an electrician nor an expert in the NEC, but my understanding is it is allowed, provided conditions are met (i.e. having the two branches on different poles, having the breakers tied so that if one trips the other tips.) This configuration would preclude a GFCI breaker. Since AFI breakers are required in living spaces, this would appear to be a moot point, anyway.

Most importantly, the requirement that the breakers be tied together would negate the benefits of having two circuits.

Given the issues, I think it would be best to pull 2 sets of wires.

[sfsuphysics]

A little searching through the NEC 210.4(B) states there needs to be "Disconnecting means" basically a way to turn off both simultaneous, via a handle tie or something, not a common trip.

Regardless of the application, I thought the benefits of two circuits is to bring more power so you won't be anywhere closer to overloading the circuit to cause it to trip :)

[adamgoldberg]

Oh, here's a whole page on this issue: Multi-Wire Branch Circuits (http://www.ieci.org/blog/posts/view/50).

Also, http://ecmweb.com/code-basics/branch-circuits-part-one:
Disconnecting means. Where two or more branch circuits supply devices (or equipment) on the same yoke, you must provide a means to disconnect simultaneously all ungrounded conductors that supply those devices or equipment. A “yoke” is the metal mounting structure for a device (e.g., switch, receptacle, pilot light). It's also called a strap. Locate it at the point where the branch circuit originates [210.7(B)] (Fig. 2 on page 60). Individual single-pole circuit breakers with handle ties identified for the purpose can be used for this application [240.20(B)(1)]. So can a breaker with a common internal trip. This rule prevents people from working on energized circuits they thought were disconnected.

[johnike]

I went overboard, and have 4 20A breaker circuits with GFCI outlets on all.

[BeanAnimal]

A 15A circuit theoretically can provide 15*120 = 1800 watts. This is theory, not actual.

There is no theory about it... 15A at 120V is 1800W. However, a branch circuit should never be loaded to more than 80% of its rated load. The issue is not safety, but rather nuisance trips caused by the breaker running so close to the trip threshold.

I just built a new house; I'm not sure I understand why, but the electrician wired all the GFCIs with 12/2 and a 15A breaker. 20A branch circuits are typically 12/2.Fairly common and perfectly within the code. He gets to use a single breaker size that he buys in bulk and he gets to use 15A switches and receptacles throughout. If you ask to "upgrade" he charges 20% more per drop but only pays 5% more and gets to explain that not only does the breaker need changed, but so do the switches and receptacles. That said, most 15A switches and receptacle yokes are UL Listed for 20A as well.. In other words it is in easy way to offer "expensive" upgrades that are profitable. Also note that there is in fact a fairly significant cost difference between 15A and 20A AFCI breakers :)

Secondly, he may be dealing with a local AHJ that oddly interprets some line of code so he avoids the issue by doing work a certain way.

[BeanAnimal]

A little searching through the NEC 210.4(B) states there needs to be "Disconnecting means" basically a way to turn off both simultaneous, via a handle tie or something, not a common trip.

Regardless of the application, I thought the benefits of two circuits is to bring more power so you won't be anywhere closer to overloading the circuit to cause it to trip :)

Yes, shared neutral circuits must have handle ties but that does not mean they need to be common trip. The handle tie is a "disconnecting" means. So that if the breaker is thrown, all current carrying conductors on the shared circuit are de-energized. However, in a "trip" scenario, with no common "trip" device, one breaker may trip and the other handle tied breaker may not even though the common handle is in the tripped position.

[BeanAnimal]

Re: pulling 3 conductor wire and sharing the neutral, I've seen that in older houses, not in newer houses.Still an extremely common practice (or would be) except for the mandatory use of AFCI/GFCI circuit breakers. They do not play well on shared neutral circuits.

That said, there is a good argument to be made to use non afci/gci breakers in lieu of individual GFCI receptacles at the endpoints.

In commercial applications shared neutrals are highly common, especially when the low voltage branches are derived from 3 phases. Pull a single neutral in a conduit and (3) hots...


Given the issues, I think it would be best to pull 2 sets of wires.

[adamgoldberg]

There is no theory about it... 15A at 120V is 1800W. However, a branch circuit should never be loaded to more than 80% of its rated load. The issue is not safety, but rather nuisance trips caused by the breaker running so close to the trip threshold.

Well, not to quibble ... but ... yes, 15 * 120 = 1800, but add any wire between a (perfect theoretical) breaker and a (perfect theoretical) load, and losses due to the wire makes the available wattage at the load before tripping (at least a little) less than 1800W (maybe just a tiny bit, I dunno how much, but in any case, that's why I said "theoretically").

Fairly common and perfectly within the code. He gets to use a single breaker size that he buys in bulk and he gets to use 15A switches and receptacles throughout. If you ask to "upgrade" he charges 20% more per drop but only pays 5% more and gets to explain that not only does the breaker need changed, but so do the switches and receptacles. That said, most 15A switches and receptacle yokes are UL Listed for 20A as well.. In other words it is in easy way to offer "expensive" upgrades that are profitable. Also note that there is in fact a fairly significant cost difference between 15A and 20A AFCI breakers :)

Interesting but not what he did. Also, the price difference for a whole house of 12/2 vs. 14/2 seems like it'd be not inconsiderable. (Example: Home Depot has 250' 14/2 for $46, 250' 12/2 for $70 ... if 12/2 is 50% more expensive than 14/2, it seems strange to use it when unnecessary). But you seem to know much more about this than I.

Secondly, he may be dealing with a local AHJ that oddly interprets some line of code so he avoids the issue by doing work a certain way.

What he did was wire all GFCI-protected circuits with 12/2 on 15A breakers, all non-GFCI (including AFCI) with 14/2 on 15A breakers. Except for the 20A circuits I ordered for the equipment rack, espresso machine, and my office -- my equipment room looks like yours, BeanAnimal, with a 45U 19" rack -- and I had to specify that I wanted NEMA 5-20R receptacles which he didn't have in his truck at all. I didn't expect him to have L5-20R for the ceiling-mounted outlet for the equipment rack :)

Alas, I seem to have wandered from the original topic :(

[sleepydoc]

While we're all debating the NEC, I think the best option for the OP would be to call his local electrical inspector and check out his planned wiring ahead of time to make sure it meets code (or the inspector's interpretation of code.) Ultimately, he/she is the one who determines whether it passes anyway.

I realize many people don't bother having projects inspected, but I would recommend otherwise. First, it helps ensure you're meeting code, and second, if there should be a fire or some other un-towarad event, your insurance company can't come back and deny the claim because of 'unapproved wiring.'

[adamgoldberg]

I think the best option for the OP would be to call his local electrical inspector ...

I realize many people don't bother having projects inspected, but I would recommend otherwise. ... your insurance company can't come back and deny the claim because of 'unapproved wiring.'

Yes, yes, a thousand times yes.

Oh, and some jurisdictions require that an actual licensed electrician do/supervise and/or approve the work.

[jolopy409]

Pretty much what everyone else said 2 12/2 lines to GFCI outlets. Outlets are cheaper than the GFCI breaker and it if it trips you reset at the receptacle verses the basement. But either would work. No matter what "code" is in your area, 12/2 dedicated lines like you would put on your kitchen counter by a sink is what I would do.

I wouldnt use Arc fault breakers. In my experience as a landlord they trip alot from tenants pulling plugs out when something is still powered or trip all together. With a tank and all the stuff plugged in and maintenance the possibility of it tripping i feel is to high. Pulled them out and replaced with standard 20a breakers.

Put the 2 500 watt heaters and your skimmer on one outlet and the rest on the second and you should be fine. Keep it to about 1700 and it wont trip.

Disclaimer- Im not an electrician but I own a 100 yr old house and rewired and corrected it.

[jolopy409]

if there should be a fire or some other un-towarad event, your insurance company can't come back and deny the claim because of 'unapproved wiring.'

"it was already in the house when i bought it" lol

[adamgoldberg]

"it was already in the house when i bought it" lol

You want to bet $n00,000 on the insurance company bending over backwards to NOT reject a claim? Seems like a a few hundred bucks would be really cheap insurance against that happening.

[jolopy409]

#itsAjoke

[BeanAnimal]

, it seems strange to use it when unnecessary). But you seem to know much more about this than I. Sometimes it goes back to the local AHJ and an odd interpretation of the code, or even a pet-peeve that the contractors have to deal with (and pass on to the buyer). Who knows...

FWIW... that "equipment rack" is just the termination point of the LAN, Voice and COAX drops. It holds a switch or two and now my (2) 1U Atom servers (AD/FILE and Firewall/wireless controller/vpn terminator). It also holds the legacy Avaya Partner ACS phone system that I can't ever find the time to replace.

The rest of the equipment for the home theater, TVs, sonos equipment, amplifiers, etc is under the stairs.... for a 30x30 ranch, I have far too little space for the amount of equipment I have.

I have a FULL 200A 32 space panel and a nearly full 18 space 80A sub in the house and a 50A sub in the shed (wood shop). Everything in my home is on its own breaker.

[BeanAnimal]

I would also add that sadly, as much as I demand that folks hire qualified help, follow the law and code... sometimes (most of the time) getting the AHJ involved with a simple branch circuit addition opens a can of worms that will end up costing thousands more, not hundreds more... Your best bet is to NOT call the AHJ and ask for help. Instead find a LOCAL qualified electrician that knows (AND WORKS) the area, the AHJ and the inspectors. He or She will tell you the best way to move forward without getting yourself in a bind by trying to launch the project on your own. Sometimes just having the "pro" involved sets the entire tone and course the AHJ will take with regard to approving and signing off on the project.

[Sethjamto]

Thanks again guys! I'll probably run (2) 12/2 wires and (2) 20a breakers and call it done. Electricity is the one thing that scares me, so I'll have a buddy come by to inspect and do the final hookup (he's an electrician).

[Sethjamto]

I'm not an electrician either... at least a legal one :D However my entire house is wired with sets of shared neutrals with really old wiring. I do concede that it might not be up to code today, and in the large scale scheme of things is a major PITA to deal with if you want to swap panels out. That said I've never had an issue with GFCI's tripping on the house wire. As to the breaker issue, I believe you need a tie together the two 120 single pole breakers together, or use a double 120v, such that if you need to turn off the power it turns off both poles.

That said, for practicality 2 12/2 circuits isn't that much more difficult, just twice the holes you need to drill, twice the staples, twice the wire (although for some reason 12/3 is disproportionately more expensive than 12/2 based upon how many conductors you're getting, maybe the red sleeved copper is more expensive *shrug*).

That said, depending upon what the existing plugs that are "shared" are plugged into I might only run a single 20amp outlet. But if said shared load is with a TV, HT system, stereo then yeah all bets are off. Of course I run pumps that are quite a bit more energy friendly than what the OP is going to put on the system.

What are you running and how much more efficient are they??

[BeanAnimal]

Well, not to quibble ... but ... yes, 15 * 120 = 1800, but add any wire between a (perfect theoretical) breaker and a (perfect theoretical) load, and losses due to the wire makes the available wattage at the load before tripping (at least a little) less than 1800W (maybe just a tiny bit, I dunno how much, but in any case, that's why I said "theoretically").

Just for the exercise of it....

Typical 12/2 Romex = 0.1588 Ohms per 100 feet.

So given a typical 50 foot run (100 feet of total current carrying conductor) the voltage drop is about 2.4 Volts. That equates to 35W of power dissipated in the wire.

Given 1800W - 20% loading (the NEC value given for max circuit loading) = 1440W. So the 360W derating of the circuit is well beyond the 35W line loss in the circuit.

That said, a 15A circuit breaker does not "trip" at 15A. They trip on time-current curves that vary by model.

So without fiddling with transmission line issues and parasitic heat/resistance, lets assume we drive the breaker at 1800W + 36W and some wiggle room to account for terminal resistance, etc... so 1900W

1850W @ 120V = 15.83A presented to the 15A breaker on the fully loaded 50' 12/2 branch circuit.

For the GE Residential GFCI breakers the curve:
http://www.geindustrial.com/publibrary/checkout/GES-9881?TNR=Time%20Current%20Curves|GES-9881|generic

From the graph it appears that the 15A model will trip at about 1000 Seconds when loaded to 17A, but likely not before that. So loaded to 16.83A (steady state) it will not trip :)

In fact, you could run the breaker at about 29A for 20 seconds before it trips and close to 100A for 1 second before it tripped!

In any case, the reason we only want to load the circuit to 1440W is to prevent the breaker from running in an area where a small spike (motor inrush, etc) would cause it to trip.

No for fun... go put a clamp on meter on your heavily used branches and figure out if it would be cheaper to have run #10 to reduce line loss :)

[adamgoldberg]

Well, a bit more real-world... my APC Smart-UPS 750 under my desk reports that it's input voltage is 122.4VAC, and the history shows that occasionally it gets as high as 125.5.

My only experience with breakers tripping is FLASH! BANG!! dark. I don't know about a 1 second delay ... I suppose with a very high resistance short?

[sleepydoc]

My only experience with breakers tripping is FLASH! BANG!! dark. I don't know about a 1 second delay ... I suppose with a very high resistance short?

As bean said, most breakers don't have a 'hard' trip current; a 15 amp breaker will trip more slowly at 16 amps than at 60 amps. Whey you shorted out the light socket and got 'flash bang,' you were probably closer to 60 amps.

To the OP: If your buddy's an electrician, why didn't you just ask him? He could give you more educated advice that all of us wannabes around here.

[adamgoldberg]

Whey you shorted out the light socket and got 'flash bang,' you were probably closer to 60 amps.


Actually, I was standing nearby as an electrician working in a live 200A panel ... um ... did something, KABAM!! It scared the **** out of both of us.

He told a story about accidentally cutting a live cable ... in addition to the noise and light, it vaporized about half of his angle cutters. I'm pretty sure I stayed several additional feet away from him after that.

[sleepydoc]

ummm... maybe that's a sign that you need a new electrician!

[adamgoldberg]

LOL. Everyone has a story about being young & stupid, I think.