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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 2742
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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can i replace a 20amp breaker with a 30amp

Customer Question

can i replace a 20amp breaker with a 30amp
Submitted: 7 years ago.
Category: Electrical
Expert:  Mike replied 7 years ago.
Do you know what size wire is used for this circuit?
Customer: replied 7 years ago.
well my living room two bed rooms and furnace all our on one 20amp breaker and it keep blowing so i was wondering if i could put in a 30amp breaker
Expert:  Mike replied 7 years ago.
Without knowing what size wire you have I can't tell you with 100% certainty, but I can tell you this: If you have a 20 amp breaker on the circuit now, there's a very, very good chance that you have #12 gauge wire for this circuit. Either #12 or #14 (which is smaller than #12) is used for general use circuits like yours. It would be an extremely rare and special circumstance that #10 wire (which has a 30 amp rating) would be ran for a general use application in a home. And then even if #10 was used, it would be even more rare for the circuit to not already have a 30 amp breaker.

That being said, you cannot simply change a 20 amp breaker out for a 30 amp. If your circuit breaker is tripping that means you either have a short occuring or the circuit is being overloaded. If you change out the breaker, the wire will not have adequate overcurrent protection which is a fire hazard. The wire is only rated for 20 amps, so installing a 30 amp breaker would allow more current than the wire can carry. I'm sure you can see how this could be dangerous.

My advice is to have an electrician install an additional circuit or two to split up the load a bit so there isn't so much running on one circuit. This should solve your issue with the circuit tripping if it is indeed being overloaded.

Expert:  electrifier replied 7 years ago.

30 amp breakers are NEVER allowed on receptacle or lighting circuits in a home. This is a code violation. If you blow 20 amp breakers frequently either the breaker is weak or the circuit is overloaded. Try a new breaker or remove some of the load on the circuit. Increasing the overcurrent protection is not allowed by code.

Expert:  Mike replied 7 years ago.
I appreciate your agreement with the post Bobby... that is correct, you cannot simply change out a 20 amp breaker with a 30 amp breaker. It's certainly in the customer's best interest to install additional circuits to break up the load on the existing circuit.

I do want to clear up some potentially misleading information though... there are several situations where a 30 amp lighting or receptacle circuit can be utilized in a home. A 30 amp dryer circuit is installed in almost every home. A 30amp circuit to supply a lighting contactor which is in fact utilized in several larger scale homes along the SC coast is also absolutely code compliant. It can be misleading to use blanket statements like "NEVER" as it's very evident that there is indeed several situations in which 30 amp circuits can be utilized.


Edited by Mike Pettinato on 12/7/2009 at 8:02 AM EST