[brabey]

Hi im new, My concern is that in February 2011 I upgraded a subpanel in my shop from 50 amps to 70 amps running from a 100 amp house main panel, off a 70 amp breaker to a sub on the outside of the house where there is another 70 amp breaker around 25 feet. I then went from that panel to the shop where there is another 70 amp breaker. The last run is about 20 feet. I ran four 4awg wires. The last PVC LB has a black smokey look on top. It dont appear to come off very easily. I live in Southern New Mexico and its getting up around 103 degrees. I opend the LB up and dont see any thing melted or discoloration inside. Can the sun and heat discolor the LB in this way. Soory this is so long. Thanks for any help. [email protected]

 

[zpm]

The last PVC LB has a black smokey look on top. It dont appear to come off very easily. I live in Southern New Mexico and its getting up around 103 degrees. I opend the LB up and dont see any thing melted or discoloration inside. Can the sun and heat discolor the LB in this way.

Yes. Sounds like PVC sunburn.

 

[brabey]

I did'nt know that could happen. Thanks for your reply.

 

[a7ecorsair]

If the inside of the LB looks fine then the discoloration is from the outside and not from a hot wire.

 

[mpoulton]

Gray PVC will turn brownish/purplish/black in about one season in the desert southwest.