Wiring new electrical for 300g tank

Sethjamto

New member
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

New member
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

New member
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

New member
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

New member
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

Team RC
+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

New member
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
 

viggen

New member
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

Active member
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

New member
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

New member
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

New member
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

New member
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

New member
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

New member
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

Team RC
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

New member
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

New member
Oh, here's a whole page on this issue: Multi-Wire Branch Circuits.

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.
 
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