Bath fan throwing breaker
 

So I put a bath fan and light in a bathroom off a master bedroom. There had already been a light there, I just knocked out the junction box and made the hole bigger. Everything works fine now except when you run a blow dryer. You can turn off the fan and everything else in the room but if you run a blow dryer it will throw the circuit breaker after about a minute. The bedroom and bath are on the same circuit and the fan is the second thing on the wire, then it goes on to a whole bunch of other stuff.

Sounds like the circuit was close to overload and the added load from the fan is pushing you over the top. You could check this with an ampmeter.

Hair dryers generally use about 1200W, which is most of 15A circuit. If there is anything else on the circuit, that could be enough for it to trip. It is always possible there is a weak breaker.

Current code requires bathrooms to be on a dedicated 20A circuit, which is usually enough to run blowers, fans, etc. If the fan is also a heater fan, that should have its' own circuit. GFCI outlets are required, and AFCI may be required, check local code.

Same problem we had I ended up spliting it up so bedroom was separate 15 amp circuit and bath fan and light along with kitchen hallway and laundry lighting were moved to a 15 amp lighting circuit and a new 20 amp dedicated circuit was added for the bathroom counter. You just have to figure out where it goes from one room to the next to break it up. I ended up fishing and pulling three wires. If you have attic or crawl space sccess you should be able to fish the wires.

Hair dryer nameplate says 1875W?

The bath and bed room are on a 15amp switch. Is it possible to install a 20amp switch in its place, or would the wires fry? And burn the house down.

The whole house though is pretty pathetic. The entire outside of the house is on a 15amp switch and if you run a circular saw for very long it will through.

NO! You can not replace a 15 amp breaker with a 20 amp breaker. You will burn your house down. Ask your insurance company what they think about that idea!

You need to run new larger gauge wiring to use a 20 amp breaker.

Things like this are a daily annoyance. It can make daily life a WHOLE lot more pleasant to run a few new 20 amp circuits to power hogs like the bathroom, kitchen refrigerator/counter top, where you plug in the vacuum, etc.

Might want to get an estimate from an electrician. In some cases it is easy to run a new line, especially if you have an accessible attic or basement.

That would be almost a 16amp draw. Must be one hell of a blow dryer.

I tried 2 different hair dryers and both did the same thing.

hair dryers
 

Bigger bathroom breakers = more hair dryer watts = bigger bathroom breakers
http://www.nextag.com/hair-dryer-watts/stores-html

And U.S. houses went from 60A service to 200A over how many years?

My girlfriend's blow dryer uses 1875W as well (on the High setting).

It's basically a hair care product and space heater all in one.

Yes, 550 BTU/hr.


I guess you could switch the wire to your bathroom breaker to another breaker of equal size in your panel. If this breaker also trips then it's ~75% likely that your bathroom circuit ampacity really is being exceeded and the original breaker is not tripping at below rated current value.
For higher certainty try yet another breaker.

fan, hairdryer on same circuit = blown breaker:yes: need to figure out how to get new circuit to bath or dryer...

The circuit needs to be upgraded to 20a, but you'll need to use #12 wire. Can be a pretty big project. You'd have to locate the cable run from the breaker to the first point of use, replace it, then replace every cable that runs from the 1st point to others, and so on.

What's your main breaker size? 100a? Got any pics of the panel to share?

Main switch is a 200amp.