# Dedicated circuit sizing

Ok, so I recently bought a new home and have moved my laser (60w Chinese omtech) to the utility room. The use is the only outlets in the room are for the sump pump.

Bummer…
So I am going to run new wiring for a dedicated circuit for the laser and laser equipment. I’m not sure between 15 or 20 amp circuit breaker and wiring. The circuit will have the laser, a laptop, and possibly an air compressor for air assist (though that may end up on a different circuit of outside with a blower for the fume removal). I’m thinking 20 Amp would be the best, but obviously that comes with a higher cost. Also, I’m unsure if I should use a GFCI/AFCI circuit breaker or just a standard breaker.

Thought or suggestions are greatly appreciated.

Not shure which voltage you have, but calculation is easy:

Volt x Ampere = Power
115V x 15A = 1725W
115V x 20A = 2300W
220V x 15A = 3300W
220V x 20A = 4400W

This is a theoretical calculation, but I think your equipment is far away even from the 1725W.
If you have a food processor in your kitchen it will take much more power than your laser setup.
See what´s installed for the kitchen as line protection.

If you are doing it yourself, I would go with a 20A for future upgrades. You should in my humble opinion go with a “smart wifi circuit breaker” so you can monitor the energy usage and bounce it off your bill for helping will shop labor time

While you’re snaking wires, run two of them and put the compressor on a separate breaker. The additional impedance of two wire runs will (tend to) tamp down the horrible spikes caused when the compressor motor kicks in and save your sanity later on.

The only difference will be a run of 12 AWG wire vs 14 AWG, as everything else costs about the same. A quick check says 250 feet of 12/2 is \$140 vs \$110 for 14/2: whatever you’re paying for labor will swamp the difference.

That will likely be determined by Your Local Codes, rather than anything sensible.

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I’m sure @ednisley meant to include a ground… You can get 12/2 with ground and without ground…

I agree with his recommendations… Especially separate feeds for each.

Always ground this stuff… If you are anywhere outside, it’s probably code to have a gfi… I had my panel upgraded and power to the garage… a gfi was required by code.

Always ground things (I know I’ve already advised this)… especially Chinese stuff… it’s less of a shock if you just pop a breaker…

My compressor is a California Air and draws 12A when it runs…

Probably more at start up, one of the people there suggested to use a 20A breaker instead of 15A…

Look at your compressor and see what it draws…

Good luck

These days, they all have a ground wire. The /2 and /3 designates the number of “power” wires in addition to the ground.

They wired this house with BX armored cable back in the mid-50s: I am way glad to live in the future where Romex is a thing!

Thank you everyone for the responses. I’m going to go with the 20A dedicated AFCI/GFCI breaker. Keeping peripherals limited to just the laptop to run the laser, some LED lights to see inside, and the cooler. Keeping the air assist on a separate (existing) power source in the utility room. My previous set up used a 15A breaker and I never had issues (but it was without the air assist), but I THINK the 20A circuit is what the laser manual called out, and the air assist would definitely be a large draw anytime it kicks on. Start up transients are a BIG deal.

In the US, at least where I am, the Romex ALWAYS comes with the ground wire. So everything will be grounded. Ednisley is correct, the 3 or 4 in the Romex designates the number of “live” wires, such as a 3-way switch or something similar.