15 amp vs 20 amp


Old 05-06-12, 10:08 AM
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15 amp vs 20 amp

Hello again,
I am trying to figure out whether to wire 3 separate circuits 12g/20amp or 14g/15amp for my dishwasher( currently rated for 7 amps, newer models I have seen are 9-10amps), a circuit with 2 lights and a mini fridge on it, and lastly a circuit for my workshop (the biggest tool I have currently is a 15amp circular saw).

In speaking with the experts at Home Depot they told me I should use a 15 amp circuit for my dishwasher/power tools since if I use a 20 amp circuit it will not trip the breaker if I need it to(no idea what this means). I know breakers trip when they are overloaded, but what is the danger they are talking about?

My thinking is just put in all 20 amp circuits because I can put more on a line if I had to.

Could someone please explain to me what they were talking about, and what I should do, 15a or 20a???

Thanks in advance,
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Old 05-06-12, 10:57 AM
chandler's Avatar
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Thee "experts" at HD know where the stuff goes in the shelves, and that's pushing it. Pull the trigger on your 15 amp saw and let the starting amps peak at 17 amps.....protect it with a 15 amp breaker. NOT. Not sure about your dishwasher only using 7 amps with a heating cycle. I would run all 20 amp circuits on 12 gauge cable/wire.
What they are alluding to is a blatant over protection of the circuit If there is a problem, the wiring you have will handle the overload and the breaker will trip.
Old 05-06-12, 11:09 AM
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Chandler's advice is solid and will not trouble you at all.

If your looking to save a little money, you would be likely fine running a dedicated 15 amp circuit to the dishwasher, and another 15 amp circuit for the lights/ mini fridge. The workshop circuit should be a 20 amp circuit for sure.

Of course, the only money you will save is the cost of the wire, and that would only be around $20
Old 05-06-12, 11:40 AM
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Is the workshop attached or detached?
Old 05-06-12, 01:20 PM
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For sure 20amp on the garage/workshop. I like 15amp for lighting circuits, it makes wiring a bit easier, and yes, on small lighting circuits one could make the argument 15 is safer than 20. THe DW could go either way. If its a dedicated DW only run and I'd certainly consider 15a for this. I've just read of a bunch of DW going up in flames lately due to product defects, although there is no evidence that a 15a circuit would help this issue. Can't hurt, though. If I had the option, i'd really consider a AFCI if we are talking one of the affect models. Won't name them here, but do a search, and you will be shocked.

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