UL Solutions Question Corner

Article archives by UL Solutions pertaining to electrical listing questions asked by electricians and inspectors.

Why does the Listing limit these meter sockets for residential use only?

Question: Meter sockets I have noticed some meter sockets that are marked “Residential Use Only.” Why does the Listing limit ...

My jurisdiction recently adopted the 2008 NEC and I was wondering when UL is going to add the 2008 NEC to the Code Correlation database?

Question: Code correlation database I do plan review and often use UL’s online Code Correlation Database to assist in determining ...

I have seen these power strips that pop up out of a counter in a kitchen, are these power strips Listed for use in kitchen counters?

Question: Power strips in kitchen I have seen these power strips that pop up out of a counter in a ...

How can these computer carts in hospital rooms be Listed when they conflict with the XBYS Guide Information?

Question: Relocatable power taps I have seen computer carts in hospital rooms and exam areas that are provided with relocatable ...

How do I know if a switchboard or panelboard is Listed for top or bottom feed or both?

Question: Switchboard How do I know if a switchboard or panelboard is Listed for top or bottom feed or both? ...

How do I know if a meter socket was evaluated for a top or bottom feed or both?

Question: Meter socket How do I know if a meter socket was evaluated for a top or bottom feed or ...

What is AWM and can I use it for field wiring and comply with the NEC?

Question: AMW wire I encountered some wire that was marked AWM and was marked with a style number, yet there ...

In the 2008 NEC, Section 406.8(A) and (B) require receptacles installed in damp or wet locations to be weather-resistant. How will these be identified?

Question: Receptacles in damp or wet locations In the 2008 NEC, Section 406.8(A) and (B) require receptacles installed in damp ...

Some ground-fault circuit interrupter (GFCI) receptacles that carry a rating of 20 amps are provided with a 15-A NEMA configuration receptacle. Can you tell me why the GFCI is not the same?

Question: GFCI without 15-A NEMA configuration receptacle A standard 20-amp rated duplex receptacle has a NEMA 20-A polarized configuration, however, ...

Are concentric and eccentric knockouts on panelboards Listed for bonding at over 250-volts? How about on outlet boxes?

Question: Knockouts on panelboards Are concentric and eccentric knockouts on panelboards Listed for bonding at over 250-volts? How about on ...