Can anyone point me to a code section, if any, on what the requirements are for penetrating dry-type transformer with weather shield installed outdoors in wet location. We have conduits stubbed up to hit the bottom of the transformer for the primaries, the secondaries will come out the side through a rigid nipple and into the free standing piece of gear. My question specifically is about the rigid nipple, do I have to use sealing locknuts, myers hubs, or what? I have been told that as long as the penetration is in the bottom 1/3 of the transformer, nothing beyond the standard locknut is required. Is it correct, or I am being misled?
NEMA 3R transformer penetrations
- Thread starter yursparky
- Start date
- Status
- Location
- Massachusetts
I can not find an section that directly addresses that.
If we look at 312.2(A) or 314.15 we can get an good idea of what to do but I really do not think either of those sections directly applies to transformer enclosures.
If I had to pick one I would say it is a "Transformer Cabinet" and apply 312.2(A)
If we look at 312.2(A) or 314.15 we can get an good idea of what to do but I really do not think either of those sections directly applies to transformer enclosures.
If I had to pick one I would say it is a "Transformer Cabinet" and apply 312.2(A)
If you are outdoors (NEMA 3R enclosure) you would be required to put myers hubs on all horizontial conduits entering the cabinet in order to retain the 3R rating of the equipment. Also, you must exit the equipment at a point lower than the top of the coils since your conductors can not be above the coils inside the transformer.
Kevin
ICC/IAEI Commercial Electrical Inspector
Kevin
ICC/IAEI Commercial Electrical Inspector
- Location
- Massachusetts
KevinVost said:
Kevin check out the two sections 312.2(A) and 314.15 I mentioned, they do not require what your saying.
You do not have to use a Myers hub, sealing locknuts would do it.
As far as 312.2(A) If you enter below the live parts any fittings are fine and if you enter above the live parts any wet location fittings are fine.
hdpeng
Member
- Location
- Acworth, GA
A chain is only as strong as its weakest link. In your situation you ARE required to maintain the 3R rating. By putting a non-weathertight link into the side of the transformer (where water will most likely seep in during rain) you will violate its 3R integrity. If this weren't the case, what would be the purpose of 3R, or 4X, etc. The manufacturer will legally disclaim any warranty if something goes wrong, and instead of buying & installing some weathertight bushings the first time around, you could end up buying them the second time... along with a new transformer... & possibly more cable & conduit.
Last edited:
- Location
- Massachusetts
hdpeng said:
David PLEASE read 312.2(A)
If you enter below the live parts you do not have to use WP fittings.
Keep in mind 3R is only rain tight, not water proof.
The penetration is below any live parts in the transformer, and I will have just plain locknuts.
As far as the transformer being 3R - only the weathershields make it so when added to N1 transformer. The whole bottom of the thing is riddled with holes, any water is more likely to get splashed back in from the bottom, then leak through the side penetration.
As far as the transformer being 3R - only the weathershields make it so when added to N1 transformer. The whole bottom of the thing is riddled with holes, any water is more likely to get splashed back in from the bottom, then leak through the side penetration.
hdpeng
Member
- Location
- Acworth, GA
That's what I said (see original post... weathertight... not watertight). It would be prudent to get verification from the mfg., too, just for CYA.iwire said:
- Location
- Massachusetts
hdpeng said:
David I am not following you and it may just be I am misunderstanding you.
If I enter a 3R enclosure below the level of the live parts I can use any fitting at all. I do not have to check with the mfg. although I certainly have to enter the unit the area they specify.
CYA?
Heck that is when I send an RFI to the EE so it can be his A in need of C. - Status