I'm an electrician and want to help you with this question.
An MH breaker may be used in place of an MP type, only if the label on the panel says that the MH is acceptable for use in the panel.
Even if the MH type physically fits, if it is not one of the types listed on the label it cannot be installed without violating the National Electrical Code. Now, I know breaking some law that no one will ever likely come into your house to check on (like the mattress tags), the fact is that the panel is UL listed because it was tested with all the breakers the manufacturer included. The panel and breakers are UL listed only when used together. If you install a breaker that was not tested for use in that panel (even if it was tested and is UL listed for use in another panel), the UL listing is considered voided.
A voided UL listing - not much to worry about, right? Well, yes and no. really If there should be an electrical fire in your home, and the the FD investigates (they almost always do) to determine the cause - and an improper circuit breaker is found - your insurance company may not be quite so willing to to cut you a check to cover your losses.
So, think about it. Why gamble with a circuit breaker if it isn't approved for use in your panel when you can probably get the right one to begin with?
Answers & Comments
Hi Dave,
I'm an electrician and want to help you with this question.
An MH breaker may be used in place of an MP type, only if the label on the panel says that the MH is acceptable for use in the panel.
Even if the MH type physically fits, if it is not one of the types listed on the label it cannot be installed without violating the National Electrical Code. Now, I know breaking some law that no one will ever likely come into your house to check on (like the mattress tags), the fact is that the panel is UL listed because it was tested with all the breakers the manufacturer included. The panel and breakers are UL listed only when used together. If you install a breaker that was not tested for use in that panel (even if it was tested and is UL listed for use in another panel), the UL listing is considered voided.
A voided UL listing - not much to worry about, right? Well, yes and no. really If there should be an electrical fire in your home, and the the FD investigates (they almost always do) to determine the cause - and an improper circuit breaker is found - your insurance company may not be quite so willing to to cut you a check to cover your losses.
So, think about it. Why gamble with a circuit breaker if it isn't approved for use in your panel when you can probably get the right one to begin with?
I hope this helps & good luck!