[just_a_sparky]

yes 30 amp would be fine

 

[MEISENBURG]

So loading up to only 80%of breaker doesn't apply with a ac unit? 80% of 30 is 24amps and I would be over. But that's fine just wondering. Thank you very much.

 

[bkmichael65]

AC units are easy all the calculations have been done for you on the nameplate. Minimum ampacity for sizing conductors and max breaker, which is just what it says. Breakers need to be larger to allow the compressor to start and to protect against short circuits. The compressors internal overloads will protect the conductors

 

[wildleg]

Hey guys quick question, I have a ac unit says min. Amp 26, max breaker 45. Would I be ok with a 30 amp circuit or no because I'll be over 80% of my 30 amp breaker?

what article in the NEC are you referring to by "80% of breaker" ?

 

[MEISENBURG]

Thanks guys I just thought that it was rule of thumb not to load up a breaker more than 80%. Thanks again.

 

[just_a_sparky]

yeah. the 80% rule usually applies for branch circuits
like bedrooms , bathrooms ect... lighting and power. the AC , is dedicated

 

[480sparky]

Thanks guys I just thought that it was rule of thumb not to load up a breaker more than 80%. Thanks again.

Yep. You'll find it in the Urban Legend Electrical Code.

 

[brichter]

yeah. the 80% rule usually applies for branch circuits
like bedrooms , bathrooms ect... lighting and power. the AC , is dedicated

Really?

 

[just_a_sparky]

yes, bedroom circuits have variable loads

 

[Ultrafault]

Since nobody mentioned I will.

Put a 10 wire to that and a 40 amp breaker. If you put a 30 on it you may get problems years down the road.

 

[wildleg]

Thanks guys I just thought that it was rule of thumb not to load up a breaker more than 80%. Thanks again.

being that you are a 4th yr apprentice (according to your profile), if you are planning on taking your test and/or the contractor/master test, it would be a great idea to study the articles that apply so you know where to look for the answers to the questions that you have been asking. It is no small task to prepare for the test, and while it is perfectly ok to ask these questions, it is vital to you becoming an independant tradesman that you be able to find this stuff when you need it, and directly from the book. start at 240 and see how it leads to 440 for this item, and it will help you out.

jmso

 

[Dennis Alwon]

The mca on the unit already has 125% built in .

 

[just_a_sparky]

Since nobody mentioned I will.

Put a 10 wire to that and a 40 amp breaker. If you put a 30 on it you may get problems years down the road.

what types of problems?.. and yes obviously 10awg

 

[BBQ]

what types of problems?.. and yes obviously 10awg

As the unit gets older, or if the voltage happens to be a little low the minimum size breaker may be more prone to tripping.

The manufacturer, the NEC and UL allow a 40 amp breaker for a reason and I would take advantage of it.

 

[robnj772]

Since nobody mentioned I will.

Put a 10 wire to that and a 40 amp breaker. If you put a 30 on it you may get problems years down the road.

I always use the max not the minimum

 

[bkmichael65]

I always use the max not the minimum

^^^This. A 45 amp breaker is only a couple more dollars and may prevent getting called out on the hottest day of the year because someone's AC keeps tripping

 

[dthurmond]

The older the compressor gets the harder it is to start up . So what was ok when it was new might start tripping the 30 amp breaker .

 

[MEISENBURG]

Thanks a lot wildleg for your advice.

 

[brichter]

yes, bedroom circuits have variable loads

So what? Only continuous loads are limited to 80%.