NEMA rated panels

[rey-man]

I would like to ask everyone if a NEMA 4x and 7 has been field modified,i.e. hole penetrations for conduits, will the UL listing be voided?

Does the code address this anywhere?

Thanks in advance.

reyman

 

[jim dungar]

It is a UL issue.
UL says that their listing and labeling, is all about how the equipment was manufactured at the factory.
This is from their White Book:
"It is the responsibility of the Authority Having Jurisdiction (AHJ) to determine the acceptability of the modification or if the modifications are significant enough to require one of UL?s Field Engineering Services staff members to evaluate the modified product. UL can assist the AHJ in making this determination."

 

[don_resqcapt19]

Most enclosures are intended to have hole penetrations made in the field. There should not be a UL issue. You will have to use connectors that will maintain the required NEMA rating of the enclosure.

 

[jim dungar]

Most enclosures are intended to have hole penetrations made in the field. There should not be a UL issue. You will have to use connectors that will maintain the required NEMA rating of the enclosure.

But it is still up to the AHJ, unless the manufacturer included actual penetration (i.e. knockouts). For example, what if the installer device to mount a 2" listed hub, but cut the hole using a 'sawsall', and it was more oval than round.

 

[petersonra]

But it is still up to the AHJ, unless the manufacturer included actual penetration (i.e. knockouts). For example, what if the installer device to mount a 2" listed hub, but cut the hole using a 'sawsall', and it was more oval than round.

It is not a UL issue as long as whatever is installed in the holes meets or exceeds the UL rating of the panel. IOW, if the conduit fitting is rated as type 12, you can install it (assuming you follow the directions properly) in a type 12 enclosure without the enclsoure rating being compromised.

This is what UL says about industrial control enclosures.

The basic standard used to investigate products in this category is UL 508A, "Industrial Control Panels."

According to UL508a:

19 Enclosure Openings
19.1 All openings provided for conduit connections in the field shall be of standard dimensions. When
provided, conduit fittings shall comply with the Standard for Conduit, Tubing, and Cable Fittings, UL 514B.
For enclosures other than Type 1, as noted in column 1 of Table 19.1, the conduit openings and fittings
shall additionally comply with the requirements specified in column 2 of Table 19.1.

So you would not be able to make a hole that was not a standard size.

Tables 19.1 (conduit fittings) and 19.2 (other devices) tell you what rating of devices can be installed in holes.

These tables have two columns - "Enclosure type" and "Openings are able to be closed by equipment marked".

For example - a type 3R enclosure can have holes closed by devices marked 3, 3R, 3RX, 3S, 3SX, 3X, 4, 4X, 6, 6P, Wet Location, or Raintight.

19.3 Openings provided in enclosures for mounting components shall be covered with components
intended for such mounting. For an enclosure type specified in column 1 of Table 19.2, openings provided
for components, including ventilation openings, or observation windows, shall be closed with components
that have been evaluated for one of the enclosure Types in column 2 of Table 19.2.

Table 19.3 has alternate ratings of enclsoures based on installing devices through the enclsoure that have a lesser rating. For instance a type 4X enclosure that has 3RX, 3SX, 3X, 4X devices mounted through it becomes a type 3RX. In this case a drain has to be added and there has to be a locking mechanism available.

 

[jim dungar]

Bob,

Those requirements are for someone wanting to obtain a UL508A listing.

The OP was about field openings.

 

[petersonra]

Bob,

Those requirements are for someone wanting to obtain a UL508A listing.

The OP was about field openings.

If you look at the listing for industrial enclosures it references UL508a as the basic standard.

 

[sgunsel]

I have purchased several explosion proof enclosures from Adalet, and they all included instructions for drilling/tapping in the field.

 

[jim dungar]

If you look at the listing for industrial enclosures it references UL508a as the basic standard.

Are you saying the person field cutting a hole needs to reference UL508A before doing so, or are you saying that an AHJ should reference UL508A to see if the field work has been done correctly?

 

[petersonra]

Are you saying the person field cutting a hole needs to reference UL508A before doing so, or are you saying that an AHJ should reference UL508A to see if the field work has been done correctly?

Presumably both.

None of the stuff in UL508a is rocket science for what you can use to close holes in a UL listed enclosure and maintain the environmental rating.

This whole question came about because someone claimed you could not modify a UL listed enclosure without some kind of special dispensation. It appears to me at least, that UL has covered just about every situation you would need to for common enclosures. No doubt there are special requirements for enclosures in hazardous areas, but I would bet UL has that covered somehow as well.

 

[rey-man]

But it is still up to the AHJ, unless the manufacturer included actual penetration (i.e. knockouts). For example, what if the installer device to mount a 2" listed hub, but cut the hole using a 'sawsall', and it was more oval than round.

so, it can be done but the procedure should be acceptable? I am assuming nema 7 cannot be field modified, right?