30 amp/40 amp

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Old 07-14-16, 01:24 PM
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30 amp/40 amp

I have an older home with Federal Pacific breakers. The a/c and dryer on their own separate 30 amp breakers. However, they frequently trip. It's almost an daily occurrence with the air conditioner (which runs a lot during Texas summers) and when we use the dryer the breaker may trip two or three times per load. I am told we can resolve the problem by replacing the 30 amp breakers with 40 amp breakers. Does that sound like a good solution?
 
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Old 07-14-16, 01:28 PM
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Welcome to the forums.

What size is the wire used on each circuit?
 
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Old 07-14-16, 01:33 PM
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No, it sounds like a dangerous solution especially with the dryer.

The A/C may or may not have the correct size breaker. We need to know the "minimum circuit ampacity" and "maximum overcurrent protection device" ratings from the nameplate of the outdoor A/C unit. We also need to know the wire size feeding the unit.

This sounds more like it could be a worsening problem with your FPE panel, which are known to have significant safety risks. The panel should at least be closely inspected for heat and arc damage, and you should strongly consider complete replacement.
 
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Old 07-14-16, 02:37 PM
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The tripping may be signaling problems inside the panel or the A/C .

Upsizing the breaker creates a fire hazard.
 
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Old 07-20-16, 02:39 PM
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30 amp/40 amp

Thanks for the responses. I had an electrician take a look. Turns out the dryer is under-wired. When it was installed, the electrician used #10 wire when he probably should have used #4 or #6. We didn't have any problems for 8-10 years. We have replaced the breakers on both the AC and the dryer. The old breaker on the AC showed some signs of arcing. I am going to make plans to upgrade the wiring to the dryer. For now, things are working well. Thanks again for pointing me in the right direction.
 
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Old 07-20-16, 02:47 PM
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Turns out the dryer is under-wired. When it was installed, the electrician used #10 wire when he probably should have used #4 or #6.
Dryers are normally wired with #10 so I'm a bit baffled by the electricians comment. Was he a real electrician?
 
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Old 07-20-16, 03:38 PM
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Old 07-20-16, 05:02 PM
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Residential clothes dryers require a 30 ampere circuit wired with 10-3 cable or three insulated conductors in conduit. In addition they require an equipment grounding conductor which in the case of cable will normally be bare copper or a green insulated wire in conduit.

Older installations may have a combined neutral and ground. As long as the circuit is unchanged this may be continued to be used although it does not meet current code. In either situation the maximum circuit breaker size is 30 amperes.
 
 

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