Bathroom circuits

[jeff48356]

I'm taking a practice exam (to try to get a license in a different state), and one of the questions was on the number of branch circuits required for a house to be built with 2-1/2 bathrooms. I answered 3, but the answer key says 1. In 210.11(c)(3), it calls for at least one 20A circuit needs to be provided for bathroom receptacle outlets. I interpreted it to mean one for each bathroom, but apparently that's not the case.

Here's my logic: Consider a house full of teenagers (girls). Say two girls are using hair dryers in the morning while getting ready for school, each in separate bathrooms. Hair dryers use 1500W, so 12.5A each. If both bathroom outlets were on the same circuit, they would pop the breaker, since it's only 20A, not the 25A that would be drawn.

I always wire each bathroom to its own circuit when wiring new construction, because of that.

 

[infinity]

All of the bathrooms can share one circuit for the receptacles but nothing else.

 

[MAC702]

What you give an example of is why a designer SHOULD give separate ckts to individual bathrooms, especially for more expensive homes.

But, this is one area where the NEC decides not to be a design manual, and permits the same ckt to serve all the bathrooms, and homebuilders building to the maximum profit will take full advantage of it.

As a service call electrician, I've educated more than one house "full of teenage girls" how to reset a circuit breaker and use one hair dryer at a time; usually on the phone so I don't have to drive over.

 

[Sierrasparky]

I'm taking a practice exam (to try to get a license in a different state), and one of the questions was on the number of branch circuits required for a house to be built with 2-1/2 bathrooms. I answered 3, but the answer key says 1. In 210.11(c)(3), it calls for at least one 20A circuit needs to be provided for bathroom receptacle outlets. I interpreted it to mean one for each bathroom, but apparently that's not the case.

Here's my logic: Consider a house full of teenagers (girls). Say two girls are using hair dryers in the morning while getting ready for school, each in separate bathrooms. Hair dryers use 1500W, so 12.5A each. If both bathroom outlets were on the same circuit, they would pop the breaker, since it's only 20A, not the 25A that would be drawn.

I always wire each bathroom to its own circuit when wiring new construction, because of that.

NEC only requires 1 bathroom circuit and it can power the receptacle of and in several bathrooms only if it powers only the required receptacle at the sink basin and nothing else. lighting , no heated floor, nothing.

The NEC is generally not a design manual but minimum requirements. So your answers for the test need to be the bare minimum not what is practical.

 

[tom baker]

The other allowed method is one 20 amp circuit per bathroom, it feeds nothing else, does the entire bathroom

 

[jumper]

The other allowed method is one 20 amp circuit per bathroom, it feeds nothing else, does the entire bathroom

Which works but some people do not read the exception in total, install a fan/light/heater combo, and get tripped up on 210.23(A)(2)

 

[jeff48356]

Which works but some people do not read the exception in total, install a fan/light/heater combo, and get tripped up on 210.23(A)(2)

Yep! And 110.3(B) as well -- since the manufacturer's instructions would call for a separate 20A circuit for the unit.

 

[jumper]

Yep! And 110.3(B) as well -- since the manufacturer's instructions would call for a separate 20A circuit for the unit.

What are these things you call instructions?

 

[MAC702]

What are these things you call instructions?

The thin parts of the packing material.