Terminal Shrouds for Enclosed Disconnect

[fifty60]

I am using these ABB enclosed disconnects:

https://www.platt.com/CutSheets/ABB/RotaryDisconnects-Fusible-Enclosed.pdf


These come with fuse cover holders, but no terminal shrouds to cover the line terminals. ABB sells these terminal shrouds (please see attached).

Abb informed me that they do not fit these with shrouds, but that "The issue here is not just if the spacing exists for the shrouds to fit but the bend radius for your cables and or how you will attach cables into the enclosure.

This should be according to your local electrical code and should be reviewed as well prior to making a decision on the use of the shrouds."

I need help figuring out what parts of the code apply to this situation

 

[petersonra]

there is no code requirement to have terminal shrouds that I am aware of. use heat shrink if you are bothered by it.

 

[GoldDigger]

there is no code requirement to have terminal shrouds that I am aware of. use heat shrink if you are bothered by it.

Whether you heat shrink or the terminal shields or do nothing may affect the amount of protective equipment you need to use when opening the box, or whether you are required under your local protocols to get an energized work permit.

 

[Aleman]

I wouldn't bother with shrouds for a box of this type.
For control panel disconnects where there will be work done in the panel from time to time, I will make a plastic shield mounted on standoffs.
I know of no code issue with not having terminal covers on a disconnect. You are most likely ok as is.

 

[fifty60]

A basic Mantra for CE is to protect against the village idiot...and small children and farm animals....The concern is that even with the disconnect in the off position, the line terminals are still hot...

at the very least a HI voltage warning inside the enclosure and an arc flash warning.....the terminal shrouds would be a nice to have but I concede the argument that they are not entirely necessary...

What are the ratings for shrink tubing...can I really get tubing good for 400V and 100A?

 

[petersonra]

A basic Mantra for CE is to protect against the village idiot...and small children and farm animals....The concern is that even with the disconnect in the off position, the line terminals are still hot...

at the very least a HI voltage warning inside the enclosure and an arc flash warning.....the terminal shrouds would be a nice to have but I concede the argument that they are not entirely necessary...

What are the ratings for shrink tubing...can I really get tubing good for 400V and 100A?

Heat shrink tubing is an insulator and thus rated by voltage and not amperage.

You mentioned CE, so I would presume that indicates this design has to meet those requirements. I don't have any experience with CE rated heat shrink tubing. What looks like run of the mill heat shrink tubing shows as being UL recognized for upto 600V. I don't know what the UL recognition does for you in the CE world. Probably not all that much.

 

[petersonra]

I wouldn't bother with shrouds for a box of this type.
For control panel disconnects where there will be work done in the panel from time to time, I will make a plastic shield mounted on standoffs.
I know of no code issue with not having terminal covers on a disconnect. You are most likely ok as is.

I do not see that the typical plastic shield I usually see made does anything for you other than expose the entity that made it to additional liability for making an ineffective guard. Most of the ones I have seen are basically a clear piece of flat plastic that might give some incidental protection to someone that fell straight into a cabinet but does nothing for someone who drops a tool or grabs on to the edge of the plastic sheet, as there is almost always energized parts readily accessible behind the edge of the plastic sheet.

We make them because some of our customers want them, but I am under no illusion at all that they serve any real purpose. I have a kind of standard design that encloses things from all but one side I use on CB distribution lugs, but there is no good way to make a guard in most control cabinets that will be truly be an "effective" guard as mentioned in NFPA70E.

Most people that are asking for this are saying "fingersafe" but there is no way that these kind of guards are "fingersafe". Fingersafe means it meets IP20 requirements (at least I think that is the correct one) and this kind of guard cannot meet IP20. Not even close.

if you are making a guard like this and claiming or implying it is fingersafe you are exposing yourself to a world of hurt because it just plain is not.

if you are making a guard like this and claiming or implying it is an "effective" guard you are exposing yourself to a world of hurt because it just plain is not.

 

[kwired]

A basic Mantra for CE is to protect against the village idiot...and small children and farm animals....The concern is that even with the disconnect in the off position, the line terminals are still hot...

at the very least a HI voltage warning inside the enclosure and an arc flash warning.....the terminal shrouds would be a nice to have but I concede the argument that they are not entirely necessary...

What are the ratings for shrink tubing...can I really get tubing good for 400V and 100A?

I repair underground conductors all the time and use 600 volt rated shrink tube to insulate the repair. Current rating means nothing to insulating material as has been mentioned. POCO's repair underground medium voltage lines all the time and use shrink tubing also rated for necessary voltage for the application.

I do not see that the typical plastic shield I usually see made does anything for you other than expose the entity that made it to additional liability for making an ineffective guard. Most of the ones I have seen are basically a clear piece of flat plastic that might give some incidental protection to someone that fell straight into a cabinet but does nothing for someone who drops a tool or grabs on to the edge of the plastic sheet, as there is almost always energized parts readily accessible behind the edge of the plastic sheet.

We make them because some of our customers want them, but I am under no illusion at all that they serve any real purpose. I have a kind of standard design that encloses things from all but one side I use on CB distribution lugs, but there is no good way to make a guard in most control cabinets that will be truly be an "effective" guard as mentioned in NFPA70E.

Most people that are asking for this are saying "fingersafe" but there is no way that these kind of guards are "fingersafe". Fingersafe means it meets IP20 requirements (at least I think that is the correct one) and this kind of guard cannot meet IP20. Not even close.

if you are making a guard like this and claiming or implying it is fingersafe you are exposing yourself to a world of hurt because it just plain is not.

if you are making a guard like this and claiming or implying it is an "effective" guard you are exposing yourself to a world of hurt because it just plain is not.

I guess it all depends on if there is a "fingersafe" standard. Now the IP20 may include what is necessary for what many will call "fingersafe".

Such shield still doesn't necessarily mean it provides appropriate protection from arc flash/arc blast either though.

 

[fifty60]

Hi Petresonra, did you see the ABB guards that I attached to my original post? For BS-EN61010 UL listings are useful in some cases, and will certainly help bolster your technical file if correctly used. There is no way to make the disconnect perfect safe. IMHO having the arc flash warning and the high voltage warning on the outside of the enclosure is good enough. For good measure, the same warnings are repeated inside of the enclosure.

I would be interested in using the shrouds if they in some way offer an overall risk reduction. Some representative at ABB have told I can't use the shrouds because there is no room. Others said I can use them. And yet others said I can use them if I take into account clearance requirements. I'm trying to understand what the clearance requirements are. They have to be better than just opening the enclosure and having the open 400V terminals exposed...but that is the purpose of warning labels...

 

[petersonra]

I repair underground conductors all the time and use 600 volt rated shrink tube to insulate the repair. Current rating means nothing to insulating material as has been mentioned. POCO's repair underground medium voltage lines all the time and use shrink tubing also rated for necessary voltage for the application.



I guess it all depends on if there is a "fingersafe" standard. Now the IP20 may include what is necessary for what many will call "fingersafe".

Such shield still doesn't necessarily mean it provides appropriate protection from arc flash/arc blast either though.

Who said it was supposed to provide arc flash protection at all?

if it is underground you are supposed to use the stuff rated for use underground. it is a little different than run of the mill heat shrink.

 

[kwired]

Who said it was supposed to provide arc flash protection at all?

if it is underground you are supposed to use the stuff rated for use underground. it is a little different than run of the mill heat shrink.

Well if you are opening an enclosure with live components in it, doesn't OSHA have a little to say about protection from contacting live components as well as protection from potential arc flash? Now it is true both can be mitigated by an upstream disconnecting means - but it still has to be used to provide such protection.

Underground rated shrink tubing is more "run of the mill" for me than other types

 

[petersonra]

Hi Petresonra, did you see the ABB guards that I attached to my original post? For BS-EN61010 UL listings are useful in some cases, and will certainly help bolster your technical file if correctly used. There is no way to make the disconnect perfect safe. IMHO having the arc flash warning and the high voltage warning on the outside of the enclosure is good enough. For good measure, the same warnings are repeated inside of the enclosure.

I would be interested in using the shrouds if they in some way offer an overall risk reduction. Some representative at ABB have told I can't use the shrouds because there is no room. Others said I can use them. And yet others said I can use them if I take into account clearance requirements. I'm trying to understand what the clearance requirements are. They have to be better than just opening the enclosure and having the open 400V terminals exposed...but that is the purpose of warning labels...

If you are trying to make sure that someone cannot reach live terminals on the line side when the switch is off, the only good answer is to enclose it in a separate box inside your control panel. A type 1 box would suffice IMO. You would probably need some kind of raceway (wire way comes to mind) leading from the disconnect box to the control panel enclosure surface where the incoming power wires would be routed. That way there are no exposed wires on the disconnect from inside the control panel.

Depending on the physical geometry of the switch you might be able to add some kind of tunnel to the roof (for instance) for the incoming power wires.

 

[petersonra]

Well if you are opening an enclosure with live components in it, doesn't OSHA have a little to say about protection from contacting live components as well as protection from potential arc flash? Now it is true both can be mitigated by an upstream disconnecting means - but it still has to be used to provide such protection.

Underground rated shrink tubing is more "run of the mill" for me than other types

I do not see how a flimsy piece of insulation can provide any protection from arc flash.

It might offer reduction of risk of an arc flash incident occurring by reducing the chances of unintentional contact of something conductive with the live terminals.

 

[kwired]

I do not see how a flimsy piece of insulation can provide any protection from arc flash.

It might offer reduction of risk of an arc flash incident occurring by reducing the chances of unintentional contact of something conductive with the live terminals.

I didn't say the flimsy piece of insulation would provide arc flash protection, I said(or at least tried to say) there is a good chance arc flash protection is required for someone opening the panel if there is live components inside of it.

 

[petersonra]

I didn't say the flimsy piece of insulation would provide arc flash protection, I said(or at least tried to say) there is a good chance arc flash protection is required for someone opening the panel if there is live components inside of it.

I do not disagree with that.

This brings up the question of whether arc flash protection would be required if one were working inside the cabinet but the disconnect switch was completely enclosed separately. It seems to me the arc flash hazard might well be mitigated by such a design.

 

[GoldDigger]

Only to the extent that the manufacturer provides an arc flash energy rating for that use, of course.

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[petersonra]

Only to the extent that the manufacturer provides an arc flash energy rating for that use, of course.

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the logical extension of what you are saying is that one would need to locate the disconnect switch far enough away from the control panel that the control panel was outside of the arc flash boundary or you would still require arc flash protection while working inside the control panel with the switch off.

is that your contention?

 

[GoldDigger]

No. All I am saying is that you cannot rely on closing the door to reduce hazard unless the mfr. says it will. I was not thinking about LOTO at all.

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[petersonra]

No. All I am saying is that you cannot rely on closing the door to reduce hazard unless the mfr. says it will. I was not thinking about LOTO at all.

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You seem to be suggesting that the same enclosed disconnect has a higher risk of an arc flash just because of its location.

 

[GoldDigger]

That was not my intention. Just that a switch which is lever activated with the enclosure closed is not necessarily a lower arc flash hazard than a disconnect at the same location which requires you to open the door and pull a disconnect plug.
Common sense says that there has to be a difference but an engineering analysis may not show that it is enough to drop down a PPE level.

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