Author Topic: can I drill holes in top of MNPV12 to allow 8 strands of PV wire inside?  (Read 60 times)

rollandelliott

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why are all the holes on the combiner boxes on the bottom??
Dont' most installations have the solar panels above the combo boxes?
My 10KW installation is 12' off the ground.
Combo box is 5 ft off the ground.
Would be a lot easier to just drill a hole in the top IMHO
Would that be against code? Do i really need to  run the conduit down to the bottom of the box and run two elbows for entrance into the box?
This is outside install so I dont' want water getting in and causing arcs.
Thanks.

mike90045

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Re: can I drill holes in top of MNPV12 to allow 8 strands of PV wire inside?
« Reply #1 on: November 20, 2020, 01:39:24 AM »
There is no really easy way to seal a hole on the top of a box.  The cables funnel water right in.  Sealant may work for a couple years but sun and weather always win,  and a box full of water won't be fun
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rollandelliott

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Re: can I drill holes in top of MNPV12 to allow 8 strands of PV wire inside?
« Reply #2 on: November 20, 2020, 08:49:14 AM »
 I guess I can run conduit to the side of midnite combo box and just come up from the bottom. 
The other problem with coming through the top is the wires are close to the positive metal plate.
My home's outdoor  AC breaker box has a hole on top. came with connector and foam gasket, no leaks after 10 years so it can be done,.

FNG

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Re: can I drill holes in top of MNPV12 to allow 8 strands of PV wire inside?
« Reply #3 on: November 20, 2020, 09:42:03 AM »
No problems at all from Midnites side, you can punch holes and come in the top. As others have said make sure the cable glands seal well.

What I do is run conduit down the side as a chase and come out with the pv wire and make a 180 degree loop. I am a huge fan of drip loops anytime something is in the weather. Your example of the electrical service is a good one. The seal at the top has a raised flange and works perfectly but after so many years the SE cable starts to take on water and it runs into the box and across the conenctions.