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Does Eaton publish the contact resistance of the power breaker poles

No, Eaton does not publish the contact resistance of the power breaker poles. It is a proprietary information.

For this issue, Eaton recommends performing the Individual Pole Resistance Test (Millivolt Drop) found in NEMA AB 4.  The millivolt drop test is similar to a contact resistance test.  Eaton’s recommendation is that any millivolt reading across the breaker power pole of less than 200mV is acceptable; any power pole millivolt reading of 200mV or greater is cause for pulling the breaker from service and reviewing whether or not it is suitable for continued use.


NEMA AB 4 is available as a free download from NEMA’s web site at  Type “ab4” in the Search field at the top of the page, hit the keyboard Enter key, and follow instructions that appear for downloading the document.  Email registration is required in order to receive the document