Sealing Lockrings vs Myers Hubs

[petersonra]

What is the approved way of maintaining the enclosure NEMA rating with PVC conduit? Answer yes or no, for the following.


PVC Male adapter with sealing locknut on the interior
PVC Male adapter with O-ring gasket on the exterior and standard locknut on the interior
PVC Male adapter with Myers hub
PVC Male adapter wtih sealing locknut on exterior (gasket facing enclosure), and standard locknut on interior

I think yes to all (assuming the o-ring gasket is part of a listed fitting).

However, the real answer comes from UL who tells you what you must do to maintain the type rating of an enclosure. there is a series of charts in UL508a that shows what means of sealing holes works with what type of enclosures and what the type rating is of the result.

 

[Carultch]

I think yes to all (assuming the o-ring gasket is part of a listed fitting).

However, the real answer comes from UL who tells you what you must do to maintain the type rating of an enclosure. there is a series of charts in UL508a that shows what means of sealing holes works with what type of enclosures and what the type rating is of the result.

O-ring gaskets would be a 3rd party plumbing part, you'd add to the male adapter. Physically, it should be sufficient. But on paper, it may be wrong. I've never seen a PVC male adapter built for waterproofing.

In principle, it is a much better solution than a male adapter wtih a sealing locknut on the interior, since a seal on the exterior keeps water out of the opening completely.

 

[stickboy1375]

We will have to remain in disagreement on this. IMO the NEC is clear on this and it applies to any wet location rated equipment.

I concur. The NEMA definitions are very clear on their ratings.

 

[Carultch]

I think yes to all (assuming the o-ring gasket is part of a listed fitting).

However, the real answer comes from UL who tells you what you must do to maintain the type rating of an enclosure. there is a series of charts in UL508a that shows what means of sealing holes works with what type of enclosures and what the type rating is of the result.

It looks like Carlon makes an O-ring that you can apply to a standard PVC male adapter for exactly this purpose:
http://www.cesco.com/b2c/product/Carlon-E943JW-Neoprene-Flat-Sealing-Washer/334596

Guess there is no need to improvise with a plumbing O-ring.

 

[stickboy1375]

It looks like Carlon makes an O-ring that you can apply to a standard PVC male adapter for exactly this purpose:
http://www.cesco.com/b2c/product/Carlon-E943JW-Neoprene-Flat-Sealing-Washer/334596

Guess there is no need to improvise with a plumbing O-ring.

I just rob O rings from car flex connectors when using offset nipples and PVC...

 

[electrofelon]

What is the approved way of maintaining the enclosure NEMA rating with PVC conduit? Answer yes or no, for the following.


PVC Male adapter with sealing locknut on the interior
PVC Male adapter with O-ring gasket on the exterior and standard locknut on the interior
PVC Male adapter with Myers hub
PVC Male adapter wtih sealing locknut on exterior (gasket facing enclosure), and standard locknut on interior

It looks like Carlon makes an O-ring that you can apply to a standard PVC male adapter for exactly this purpose:

I would say neither of your 4 choices are technically compliant. IIRC myers hubs and sealing locknuts are only listed for RMC. I didnt know about the carlon O-rings, good to know. Before you posted that link, I would have said there is no fullly compliant way to land PVC above live parts in an outdoor cabinet.

 

[kwired]

I just rob O rings from car flex connectors when using offset nipples and PVC...

Carflex, Sealtite fittings, or even the (stupid) EMT raintight fittings, all get saved for such purposes when they were not needed with the fitting they came with - but according to some that is not proper - but is very effective:ashamed1:

IMO there is no (listed) way to land PVC in any enclosure that needs to be watertight unless the enclosure has an integral hub of some sort to cement the raceway to.

 

[Carultch]

Carflex, Sealtite fittings, or even the (stupid) EMT raintight fittings, all get saved for such purposes when they were not needed with the fitting they came with - but according to some that is not proper - but is very effective:ashamed1:

IMO there is no (listed) way to land PVC in any enclosure that needs to be watertight unless the enclosure has an integral hub of some sort to cement the raceway to.

What is stupid about EMT raintight fittings? Difficult to work with? Poor longevity perhaps? Prefer another solution?

 

[tom baker]

What is the approved way of maintaining the enclosure NEMA rating with PVC conduit? Answer yes or no, for the following.


PVC Male adapter with sealing locknut on the interior
PVC Male adapter with O-ring gasket on the exterior and standard locknut on the interior
PVC Male adapter with Myers hub
PVC Male adapter wtih sealing locknut on exterior (gasket facing enclosure), and standard locknut on interior

Meyers hubs are not intended to be used with PVC male adapters, even though it is the most common way to terminate PVC. Carlon has O rings for this, they are hard to use as there is adhesive on one side and they are fussy to install, few even know they exist

 

[ActionDave]

What is stupid about EMT raintight fittings? Water gets in the pipes from condensation all the time anyway Difficult to work with?Yes! Very difficult. Poor longevity perhaps? Prefer another solution?Go back to the fittings that worked just fine for 50 plus years

Response in red.

 

[kwired]

What is stupid about EMT raintight fittings? Difficult to work with? Poor longevity perhaps? Prefer another solution?

Originally Posted by Carultch
What is stupid about EMT raintight fittings? Water gets in the pipes from condensation all the time anyway Difficult to work with?Yes! Very difficult. Poor longevity perhaps? Prefer another solution?Go back to the fittings that worked just fine for 50 plus yearsResponse in red.

Dave mostly summed up what I feel. They tried to fix something that wasn't broken, the standard compression fitting we had been using for a long time worked fine and more water got inside via condensation then ever got in via leakage, and still does.

 

[iwire]

Dave mostly summed up what I feel. They tried to fix something that wasn't broken, the standard compression fitting we had been using for a long time worked fine and more water got inside via condensation then ever got in via leakage, and still does.

I agree as well.

 

[donaldelectrician]

I think that doing this with sealing lock nuts would be compliant. With non-sealing lock nuts not compliant, IF you needed the sealing to be compliant.

UL is pretty clear about how you can close openings in enclosures and maintain the type rating of the enclosure. Sealant is not one of the ways.

In fact, not real long ago we approached UL about doing this very thing and offered to pay them to test it so this method could be added to our UL508a procedure. They told us not to waste our money as it has been tried before and cannot pass the UL tests.

With sealing locknuts of course . I should have stated that .




Don