“Undercabinet Lighting” (FHB#158, 62-66) has an incomprehensible statement about hooking up his new circuit into a 15 or 20 amp connection. Then there is an attempt at clarification (FHB#160, 8-10), that is even harder to understand. Could someone please put this into simple English.
Suppose I want to wire a small workshop area so that I can have some overhead lights and a few outlets to run 2-6 amp power tools. ALTERNATIVE #1: May I hook this new circuit into one of the existing circuits using a junction box? I have two essentially unused circuits available in an adjacent garage, one is 15 amp and one is 20 amp. ALTERNATIVE #2: I have not opened the circuit breaker box to be sure, but it looks l like it has room to add another circuit breaker, and I could hook my new workshop circuit to the new circuit breaker.
I understand electricity (I used to teach electronics in the Air Force), and I have some hands-on experience with household circuits — I have replaced circuit breakers, wired lights and switches.
Replies
Some basic rules, there is no NEC prohibition having lighting on a 20 amp circuit. But some local inspectors do prohibit it (I don't know if that is in that locals code or just some inspectors idea).
The kitchen requires two 20 amp small appliance circuits. Those particular circuits can only be used for appliances (ie, no lighting).
In a workshop it is undesirable to have the lighting on the same circuit as the power tools. If you overload a tool and the breaker pops then you are in the dark. This is not spec'd in the code, but "common sense" (after you have tripped a breaker).
Unless the garage circuit is one that is dedicated by code and lightly loaded them you can add your lighting to it. The only limiation is that you can't do with with a circuit that is dedicated by code. These are the required circuits (kitchen, bath which should not be in the garage and washing machine which might) and hardwired circuits such as a furnace.
Bill,
Thanks for a very clear explanation. The editors of FHB would do well to commission an article from you on how to hook in a new circuit: taping into an existing line (what you can and cannot do), adding a new breaker to box, and so on.
And thanks for the advice re separating the lighting and tool circuits -- a self-evidently clever idea once someone else tells it to you.
Spike.