UL508A

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LundenFog

Member
Location
Wharton NJ
We have a remote control panel containing a PLC mounted to the ceiling. The UL inspector said we have to follow the 508A mounting standard?? that was all i could find
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
We have a remote control panel containing a PLC mounted to the ceiling. The UL inspector said we have to follow the 508A mounting standard?? that was all i could find

what UL inspector are you speaking of?

There are no UL508a mounting standards that I am aware of to be found in UL508a.

There are however, instructions for mounting enclosures that come with the enclosures that you are required to follow.
 

LundenFog

Member
Location
Wharton NJ
Inspector

Inspector

MET Labs out of Maryland.. The electrical inspector in Mass. is requiring a 3rd party UL inspection on systems that are built in 40' Shipping containers.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
It might help if you were more forthcoming regarding just what it is the inspector is objecting to. Can you post the relevant part of his report where he rejects what you have done along with a picture of what you did?
 

LundenFog

Member
Location
Wharton NJ
We have not had our formal inspection yet. He can't come to inspect until 12/1,.. so we are talking by phone to get an idea of what may not pass and fix it before the inspection. I sent the inspector the picture that is attached and he said while it is not something he had seen before he could not fail us for it. However after a conference call yesterday with our client he is stuck on the idea that if it is listed as an industrial control panel 508a then it should not be mounted on the ceiling. These containers are very tight on space and were difficult to get everything piped in. To move these boxes will take aprox. 2 weeks each to complete, so i do not want to move them unless he can site the Article that we have violated.

We just sent him a contract last night to come out Monday 11/17 for a pre- inspection walk thru I want to be ready to argue my case.

Let me know if the photo does not come attached.

Thanks
Kevin
 

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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I do not see anything really "wrong".

There are some components such as some motor starters and relays that require a certain orientation. Presumably whatever is in the box you have assembled following the component manufacturer's instructions.
 

Aleman

Senior Member
Location
Southern Ca, USA
Never seen that done before. This panel will be subject to working clearances same as any other panel. Otherwise
I would guess it's ok. I would hate to have to work in that thing.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Never seen that done before. This panel will be subject to working clearances same as any other panel. Otherwise
I would guess it's ok. I would hate to have to work in that thing.
Since the door would be on the bottom, how would you interpret the horizontal working space clearance in "front" of the panel?
And would the entire space down to floor level "below" the panel become dedicated electrical space? It seems to me that the latter would negate any advantage of ceiling mounting.
 
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Aleman

Senior Member
Location
Southern Ca, USA
Since the door would be on the bottom, how would you interpret the horizontal working space clearance in "front" of the panel?
And would the entire space down to floor level "below" the panel become dedicated electrical space? It seems to me that the latter would negate any advantage of ceiling mounting.

I guess you could stack stuff underneath but not within 3'. With space being a major consideration I assume the trailer will be stacked full. It's not mine so I won't worry about it :)
 

LundenFog

Member
Location
Wharton NJ
Update

Update

We had our inspection yesterday... and the inspector had no problem with the panels on the ceiling. However he did have an issue with panels of different depths mounted side by side. He said that all panels mounted side by side had to be the same depth to the face of the panel off of the wall. I can't find that requirement in the NEC.??

So if we have a 12" deep control panel mounted next to a standard disconnect, he wants us to build out behind the disconnect to bring it out flush with the panel.

That was the only big thing that he found... overall not bad... but it would be great not to have to move a number of these boxes out

Thanks,
Kevin
 

kwired

Electron manager
Location
NE Nebraska
We had our inspection yesterday... and the inspector had no problem with the panels on the ceiling. However he did have an issue with panels of different depths mounted side by side. He said that all panels mounted side by side had to be the same depth to the face of the panel off of the wall. I can't find that requirement in the NEC.??

So if we have a 12" deep control panel mounted next to a standard disconnect, he wants us to build out behind the disconnect to bring it out flush with the panel.

That was the only big thing that he found... overall not bad... but it would be great not to have to move a number of these boxes out

Thanks,
Kevin
Though there possibly should be rules covering depth of side by side equipment it is not specifically mentioned from what I see , only such requirements that are there are for equipment in a vertical relationship to one another - and even those have a 6 inch allowed variance in depth before you have to somehow move the shallower components to get within the 6 inch variance.

It would kind of be reasonable to expect the general minimum work space width of 30 inches to be in violation if a (up to )29.99 inch wide cabinet only 4 inches deep were sandwiched between two other 12 inch deep enclosures without spacing the 4 inch deep cabinet forward, but it doesn't really say this is unacceptable, only if it were above or below one of the 12 inch deep enclosures.
 

Aleman

Senior Member
Location
Southern Ca, USA
So if we have a 12" deep control panel mounted next to a standard disconnect, he wants us to build out behind the disconnect to bring it out flush with the panel.


Thanks,
Kevin

I think your inspector is wrong. I have never seen any panel/disconnect layout that had to meet a 'flush' front requirement. In fact, I don't think I have ever seen one built like
that because disconnects are usually not as deep as the panels. It might be the ceiling mount has the inspector concerned in some way. I am unaware of any requirement that
faces of panels and disconnects are flush. Did he give you a tolerance to work with?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I think your inspector is wrong. I have never seen any panel/disconnect layout that had to meet a 'flush' front requirement. In fact, I don't think I have ever seen one built like
that because disconnects are usually not as deep as the panels. It might be the ceiling mount has the inspector concerned in some way. I am unaware of any requirement that
faces of panels and disconnects are flush. Did he give you a tolerance to work with?

The inspector may or may not be wrong depending on just how the various devices are oriented. read the requirements carefully.
 

LundenFog

Member
Location
Wharton NJ
We are in compliance on 30" of space the 480volt panelboard and 120/240 panel are 18" apart. The inspector said that any panel or disconnect that are mounted on the same wall the face of the panels has to be the same. even if the wall is 10' and the panels are 5' apart... unless there is a door between them... because the door starts a new wall??
 
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