Technical FAQs

Ask a Question

What is the maximum ampere rated QO, Plug-On branch circuit breakers, available for use in QO load centers?

Product design features

Product Line:
QO Load Centers
Branch circuit breakers

NOTE: This is only for the QO Plug-On branch breakers and NOT the QOB Bolt-On.

1) The maximum QO single pole branch circuit breaker is 70 ampere.

2) The maximum QO two pole branch circuit breaker is 200 ampere.
a) The two pole 150-200Amp branch circuit breakers require 4-pole spaces on the load center interior.
b) The two pole 150-200Amp branch circuit breakers are NOT suitable for use in 3Phase Load centers.
c) The two pole 150-200Amp branch circuit breakers can ONLY be used in 1phase load centers rated 150amp or higher.
d) For Older QO Square D SINGLE PHASE load centers, the 150-200Amp are restricted to Series G1 load centers manufactured since 8/8/1986(date code H08Sxxxx, the date code is stamped on the wiring diagram) and series S1 or S2, rated 150 - 225 ampere and QON SINGLE PHASE load centers rated 300 - 400 ampere. The branch breaker ampacity CANNOT exceed the load center mains ampacity rating.
e) In existing QON single phase, 300 - 400 ampere load centers, when mounted in MH50 or MH53 boxes and using MHC50VF or MHC50VS or MHC53VF or MHC53VS covers, the cover should be replaced with MHC50QVF or MHC50QVS or MHC53QVF or MHC53QVS, if over 10k AIC is available. If mounted in MH68 box with MHC68VF or MHC68VS cover, no replacement cover would be required.

3) The maximum QO three pole branch circuit breaker is 100 ampere.

Was this helpful?
What can we do to improve the information ?