Expert: Master Bob - 8/24/2004

Question
i installed new main panal house 120\240. Trying bring 240 volts out to the compressor and fan for ac unit.Put in a two pull breaker a and b fase wired them together at the outside disconect to make 240 blowing the breaker.How do i get 240 out of my Panal?

Answer
Hi Phillip,

 Sorry for the delay.....we are recovering from a computer cooling fan malfunction a few days ago....online time has been limited while we've been restoring data and files...

 You didn't state the electrical specs for your central air unit....and they range in size from a 20 amp circuit to a 50 amp circuit (and up). The minimum circuit ampacity and breaker size will be stated on the unit's electrical nameplate.

 A 20 amp unit will need #12 copper.
 A 30 amp unit will need #10 copper.
 A 40 amp unit will need #8 copper.

 If the breaker is tripping - one of three things have occurred:
1). the 2 pole breaker (and wire) is sized too small.
2). the compressor motor on the central air unit is seized up and will need to repaired or exchanged.
3). there is a direct short in the wiring - either to the unit...or inside the unit.

 Please follow-up with the electrical nameplate data for your unit....and the breaker (and wire) size used at the main panel....and the disconnect size outside by the unit. This will help me to determine what may need to  be done to correct this.

Best Wishes,

Bob Osgood
Master Electrician

RKO ELECTRIC

www.rkoelectric.com