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what will happen

4K views 24 replies 12 participants last post by  operagost 
#1 · (Edited)
What will happen if I have a 20 amp outlet on a 15 amp breakervi know its not allowed but just I want to know the dangers
 
#4 ·
Why wouldn't a 20A receptacle be allowed on a 15A breaker? My understand is that the point would be that the weakest point in the system should be the breaker, and that is the case here.
 
#15 ·
The worse thing that will happen is someone will plug a 20 amp device into it and it will trip the breaker.

A 20 amp breaker with 14awg wiring is more serious though. Adding a 20 amp load will put stress on the wires that it was not designed for, and the breaker wont trip to protect the wiring.

If you have the old faulty FPE breakers, then it really does not matter what size the breakers are, it's still going to catch on fire. :laughing:
 
#16 ·
As far as the, at this point hypothetical, possibility of plugging a 20 amp load into a 15 amp circuit with a 20 amp receptacle... How many 20 amp loads are there really that would not be able to plug into a 15 amp receptacle? I can't claim to know everything that might get plugged into anything, but frankly I can't think of anything I've seen that uses the 120V 20 amp plug shape.
 
#21 ·
Answering the question, probably nothing will happen...but the NEC doesn't allow 20 amp receptacles on a 15 amp circuit. That being said, my treadmill was listed as requiring a dedicated 20 amp circuit, but it works fine on the existing 15 amp circuit. As mentioned earlier in this thread, don't use other devices when using the treadmill. And I recommend a surge protector for the electronics in the machine.
 
#22 ·
..... the NEC doesn't allow 20 amp receptacles on a 15 amp circuit....
In 210.21(B)(1) it states:

A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.

20 Amp is not less than 15, the same as 50 Amp is not less than 40. :whistling2:


Now if you wanted to install more than one receptacle (I noticed you stated receptacleS), then section 210.21(B)(3) would apply in which case you are correct.

A duplex outlet would trigger the provisions of 210.21(B)(3) in any instance.
 
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