Electrical Wiring in the Home/wiring/breaker amperage
QUESTION: my neighbor (truly) is installing an irrigation controller (for running six separate irrigation lines). it is hard-wired and requires a 15 amp service. he has a 50 amp circuit nearby with 220 volts. he wants to connect to one side of this 50amp/220 circuit and the common with a 12 gauge wire to provide power to the new irrigation controller. it sounds unsafe to me, but other than the possible frying of the controller if a surge occurs, i can't explain what else might go wrong. what do you think? thanks!
It is wrong, illegal and dangerous.
The wire will not be protected to the proper level, and if there is a short circuit, it will probably catch fire. If the circuit has a GFCI on it, doing this will cause it to keep tripping.
Also, most 220 volt circuits do not use a neutral. Ranges and dryers do, because they also have 110 volt applications, like the lights and controls. So, the only way he can use the circuit is to use the ground wire. That could cause someone who touches any metal around the area to get a shock, because unlike a ground, the neutral carries electricity.
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QUESTION: thank you for the quick and thorough reply. to alleviate the problem that i pointed out, he has wired from one side of the 220 circuit with a 12 gauge wire and the "common" that serves that circuit to a GFI outlet and then from the outlet to the irrigation controller. so i would have two follow-up questions (because i just don't understand electricity that well). First, does the GFI outlet offer any comfort in avoiding frying the irrigation controller? Second, how does one know if the "common" he has jumped is a common or whether it is a ground as your answer suggests it may be? (he did plug a tester into the GFI outlet and it indicated "properly wired" as opposed to "open ground" or any of the other options that a series to three on/off lights indicate.
No, a GFCI is used to prevent shocks, not electrical damage to materials. The reading will show that the outlet is wired correctly. However, if something goes wrong, then people can get shocked. It is just a good idea to do things right. If a fire or accident happens, his homeowners insurance can refuse to pay because it was not wired correctly.
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