Technical FAQs

Ask a Question

What is an acceptable megger reading for QMB?

Issue:
What is a acceptable megger reading for QMB?
Product Line:
QMB panelboard, switchboard with QMB distribution.
Environment:
Products sold and used in the United States.
Cause:
Testing
Resolution:
UL standards do not specify an acceptable megger reading. UL standards require a dielectric voltage withstand test be conducted at twice rated voltage plus 1000V for one minute ( phase to phase and phase to ground).

NEMA standard PB1.1, section 7.4 says a reading of less than 1 meg ohm should be investigated as a possible `` unsafe condition``.


CTA-ID : 2020078
Was this helpful?
What can we do to improve the information ?