How much amperage do I need?


New member
I'm thinking about a 150 or 165 gallon reef setup. On the wall where I'm probably going to put the tank I have two outlets. Not sure what the amperage of the circuit is, but I'm guessing probably 10 amps, as it's a living room circuit in a 43 year old dwelling. Will that be enough current to run a full monty reef setup (plan on using LED lighting, and DC pump), or do I need to upgrade the circuit? There will be other stuff on the circuit like room lamps (also LED), and a TV.

Any thoughts appreciated.



New member
Go read the breaker/fuse for that outlet.. Then you have one known..

Then sum the draws of all the equipment..
amps = watts/voltage
YOU need to gather a list of the equipment you need and do the math here based on your choices..

A 15A circuit "should" be sufficient for a tank of that size but there are so many choices for equipment that YOU need to do the work here..

Depending on the location of the tank YOU may need 1000W of heaters.. Or you need a larger return pump because you want the sump in the basement.. And hundreds of other variables..

The math is simple...

Dr. Reef

Dr. Reef at ur service
RC Sponsor
note, just upgrading the circuit may not be enough, it also depends on what wattage/amp wires are running behind the wall as well. by simply upgrading the circuit can cause heat/stress on wire IF its not rated properly and cause fire.


New member
I don't own the house yet, and I'm 2000 miles away right now. I also don't have a single piece of equipment for a tank. I'm asking because I want to know approximately how much I will need when I do set it up.


New Old School
Premium Member
My 150 draws a peak of about 3 amps with pair of Radion G4 Pros, and 3xMP40's according to my Apex history. My return isn't connected to my Apex and my heaters heaters haven't been connected, so I'll calculate their draw. 500 watts of heater will draw about 4.2 amps,, and my RD3-230 return about 2 amps with all values ignoring power factor. That puts my total draw a little under 10 amps.

Also consider the possibility of dosing pumps, different lighting choices, and the possibility of needing more heating or chilling capacity.

Now, total draw is only part of the equation. A circuit should only be run at 80% of its peak rating, and our tanks are a life support system. I would plan on having a circuit run to the tank so that you can split your circulation and return pumps onto different circuits, giving you a measure of redundancy in case a breaker trips.

Where is the house you are looking at?


New member
Also consider the whole circuit in the house not just that plug. You need to see what else in the house is on that circuit.Depending on when and how it was wired. you could have lights or even your fridge on the same breaker.

with that said you would be hard pressed to over run a 15/20 amp breaker for the average setup.


New member
Thanks guys. That's what I was after. I'll probably consider having a separate new circuit pulled for the tank when the time comes. The house was built in 1973, so I'm not that worried about overloading it. Not like it's an antique. With a new circuit I can put in GFCI on the whole thing as well.