Ok, so I am going to set up a new grow room and need some help... well just a little. I have a pretty good idea of what I am doing with electricity, but I am not an electrician. I currently have a 100amp subpanel in my garage with conduit run to a skinny 50 amp breaker in my main box. I am planning on running 7500 watts on 220V (4000 in lights and 3500 in cooling) and 2000 watts of accessories on 110V. This gives me a total amp draw of 52amp. With a 15% safety factor we have 60 amps. I am running about 40 feet from my main breaker to my subpanel, so my question is what size wire do I need to run from the main to the sub panel and what size breaker do I need in my main box?
What gauge do you have in the conduit from the sub-panel to the outlets? Make sure you got something that can handle the load. I'd pull a 220v 4 gauge solid and a nice 70amp double breaker at the mains.
I have all 12ga from the breakers in the sub panels to the outlets. They should all be over sized, I was worried about the panel to panel. Thank you for your help. I have never pulled 4ga... this should be fun.
12ga to the outlets sounds adequate. A lot of wire jizz will help with the pull. I like the wire with the plastic coating, seems to work real well when used with jizz to make the pull easy. Good luck
I actually get your calculations at 37.5a at 220v and 20a at 110v so you have some more room on your 50a circuit 12awg is correct and a 20a breaker for your accesories. 12awg is rated for 2000w at 120v which equates to 20amps. Wire jizz is a must... Hate pulling wire but it will make it all nice and pretty when your done. best of luck
When I was doing my wiring I just picked the Romex that was rated for my load and then put that inside the grey PVC (I used 20 amp i think 14 gauge). They should be rated on Amperage just get over so you don't have to worry yourself every day about a fire.
FYI I don't think they make romex in anything heaver than 10ga this in only rated for 30amps, I have also heard never to run romex in conduit because it can't disperse the heat at easy and is more prone to start a fire.