a/c feed

[evan88]

im running a feed to a water cooled a/c unit. 12,000 btu

208/230 volt
minuim amps 9
maximuin o.c.p.d 15 amps

Does that mean i should have maximum of a 15 amp breaker on this unit. Ive never seen this before

[Dallas Duster]

Yes

[fxb80]

Overcurrent Protective Device can be breaker or fuses, and yes, in this case no larger than 15A. I'm pretty sure all new equipment has the max size on the data plate or sticker.

[evan88]

i thought so. ive never seen that before. i was all messed up because when i looked at the schematic it said for a 30amp supply but the schematic is for more then one model

[awatson84]

i had a similar thing the other day and manufactuer told me to add 5 amp so i would put a 20 amp breaker in and if it makes u feel better put a fused disconnect in with 10 or 15 amp fuses but i think u will need 20 amp for starting purposes

[evan88]

so basically whatever the max ocpd is use that as your overcurrent

[mizzouhvac]

In this case 15 amps is the maximum overcurrent protection that you would want to use, either fuses or a breaker.

[evan88]

is it a common thing that the schematic shows a different incoming amperage then what the units tag says? i dont do many installs mostly maintenance

[Dallas Duster]

I would say that the unit label where the model number is will override the schematic.

[fxb80]

is it a common thing that the schematic shows a different incoming amperage then what the units tag says? i dont do many installs mostly maintenance

A schematic may cover more than one size unit and a schematic may show all possible options a unit could have, whether it actually has the options or not, so great care must be taken when reading a schematic. Could the tag be wrong? Yes, that's a remote possibility. But, if the compressor LRA on the unit tag matches the LRA on the compressor I would say the unit tag is right.

[evan88]

lra is 22

[acwizard]

The nameplate maximum overload current protection is just that. According to the NEC it must be followed. 15 is the maximum in your situation, you could use anything less than 15, but 15 is the maximum as stated per NEC section 430.52-2