Air conditioner fuse data

[David C. Macy]

I know this has been discussed many times. I get confused & want to understand.

Exterior data plate calls for a max fuse of 25 amps.
The pull out fuses are 30 amp & the breaker in the panel is 30 amp.

Shouldnt the breaker & pull out fuses either match or be lower than the data rating?

Please clarify my confusion.

Thanks

[Paul W. Abernathy]

David,

If the Data Plate says MAX Fuse Protection...it must be protected by a FUSE at some point...either at the disconnect or at the panel....but if it says Fuse/BKR then it can be either.

Now...if it says 25A MAX on the dataplate and they have it protected by a 30A...then it is wrong......as for the pullout....if that is rated for 30A and has not fuse protection or anything...thats fine as it is rated above the allowance for that unit....(IE: We use pull out 60 A unit all the time for this. )

Now...many times it will also have on the DataPlate the AMP draw of the unit....an many times for one of the size you are talking about we are looking at about 14-15 AMPS....so the best thing they should have done is put a 20A 2-pole breaker on it.......remember less is fine......if it can't handle the start up you can go to 25A....but that is the MAX as listed....

Long story short...yes the MAX should be 25A.....we get this alot and put in 20A breakers....and KNOCK ON WOOD have not been back......sometimes 25A are hard to find....not sure why...but they are......AND well....it is NEVER acceptacle to oversize here versus what the nameplate tell you....as the DataPlate clearly gives the requirements for this unit....GOOD CALL !!!

We see this alot.....woudl it be any different to place a 30A edison base fuse on a 15A circuit....you bet......same thing........

Usually again done because the installer did not have a 25A on the vehicle but had many 30A breakers....because they are more standard to have on the truck.

While the installer DID probably run 10 AWG...yes it can handle 30A as far as the WIRE goes...however it is not consistant with the manufactures rating on the equipment nameplate rating for the OCPD...thus wrong...no matter HOW you slice it.

EDIT: Sorry..had to fix TYPO's