OPINIUNS ON RACKING SWITCHGEAR BREAKERS

[bure961]

We have switchgear that has a main breaker rated as a level 4 for ppe if you were to operate it. The feeder that needs to be racked out is listed as DANGEROUS after a arc flash survey. We open and close the breakers remotely . Now after opening this cb listed as DANGEROUS would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ? There has not been any PM on gear in over 4 years or more. I would like to ask some of your opiniuns on how you would handle it. This would be fielded to electrical contractor.

 

[templdl]

We have switchgear that has a main breaker rated as a level 4 for ppe if you were to operate it. The feeder that needs to be racked out is listed as DANGEROUS after a arc flash survey. We open and close the breakers remotely . Now after opening this cb listed as DANGEROUS would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ? There has not been any PM on gear in over 4 years or more. I would like to ask some of your opiniuns on how you would handle it. This would be fielded to electrical contractor.

The question may be are the stab type connection that are disconnected when the breaker is racked out capable of disconnecting a load? Probably not and as such the breaker itself must be opened first disconnecting and load and the the breaker can be racked out. If I remember correctly the is an interlock that will not allow a breaker to be racked in or out should it be in the closed position. When racked out completely the gear that I'm familiar with there is a set of shutters that move into place to cover the energized stationary contacts.

 

[eHunter]

We have switchgear that has a main breaker rated as a level 4 for ppe if you were to operate it. The feeder that needs to be racked out is listed as DANGEROUS after a arc flash survey. We open and close the breakers remotely . Now after opening this cb listed as DANGEROUS would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ? There has not been any PM on gear in over 4 years or more. I would like to ask some of your opiniuns on how you would handle it. This would be fielded to electrical contractor.

The potential incident energy would still be available during any racking operation.
If at all possible I would use a remote racking device.

Here is a one stop shop for remote racking and circuit breaker service.
http://www.cbsales.com/
http://www.remoterackingsolutions.com/
Be safe, don't be sorry...

 

[ATSman]

We have switchgear that has a main breaker rated as a level 4 for ppe if you were to operate it. The feeder that needs to be racked out is listed as DANGEROUS after a arc flash survey. We open and close the breakers remotely . Now after opening this cb listed as DANGEROUS would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ? There has not been any PM on gear in over 4 years or more. I would like to ask some of your opiniuns on how you would handle it. This would be fielded to electrical contractor.

would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ?
By this I take you to mean switchgear main breaker.
If this is a single bus arrangement with feeder breakers fed from a main breaker then yes.
The safest way is to remotely open the feeder breakers, then open the main breaker.
With the feeder line and load side stabs dead you can safely rack out any feeder breaker.
The point being you want the line and load stabs dead before any racking is done.
Then energize switchboard in the reverse order.
If you need to rack out the main and cannot shut down the line side of it then I would recommend the remote racking device mentioned earlier to minimize risk to personnel.

 

[bure961]

would the main switchgear breaker need to be opened before racking this to the disconnect or remove position ?
By this I take you to mean switchgear main breaker.
If this is a single bus arrangement with feeder breakers fed from a main breaker then yes.
The safest way is to remotely open the feeder breakers, then open the main breaker.
With the feeder line and load side stabs dead you can safely rack out any feeder breaker.
The point being you want the line and load stabs dead before any racking is done.
Then energize switchboard in the reverse order.
If you need to rack out the main and cannot shut down the line side of it then I would recommend the remote racking device mentioned earlier to minimize risk to personnel.

The main cb is open and has label level 4. We remotely open a cb with a label listed as "dangerous" can the cb be rack out with the listing "dangerous" wwithout deenergizing the switchgear because of no ppe for "dangerous" rating.

 

[bure961]

The main cb is open and has label level 4. We remotely open a cb with a label listed as "dangerous" can the cb be rack out with the listing "dangerous" wwithout deenergizing the switchgear because of no ppe for "dangerous" rating.

Not sure about the line stabs being energized when the breaker is open , we will check the equipment manual on these ds and dsl in the morning . thanks for your input on this .

 

[templdl]

Not sure about the line stabs being energized when the breaker is open , we will check the equipment manual on these ds and dsl in the morning . thanks for your input on this .

I used to sell power and air circuit breakers both assemblies and components and am intrigued with some of the responses to the OP.
Yes, the line stabs are energized when the breaker is open and even when the breaker is fully remove from the cubical. But there are shutters that automatically move into position covering the live stationary contacts so you would have to be totally inept and it would have to be intentional to defeat the shutters in order to come into contact with the energized stabs.
It's a very simple operation. If you want yo rack out a breaker as I described in my previous post the breaker must be on the off position which disconnects the load. Since the moving an stationary contacts are not designed to disconnect a load the breaker must be in the open position. It is in the open position that a mechanical interlock is released that will allow you to rack out the breaker. It could be racked out where the shutters that flip into place covering the live stationary stabs. With extent ion rails and a lifting device the breaker can be completely roles not of its cell for maintenance or another installed as a replacement. The shutter are in place when the breaker is removed from the cell, the breaker is placed in the cell but is not allowed to be completely racked in u less the breaker in in the open position. Only when completely is the breaker allowed to be closed.
As I understand, regardless of this procedure proper personal protection is still mandatory.
Are there any other issue that remain unanswered?

 

[bure961]

Thank you all for the information and responses and time spent here . What I got from these post is even though the breaker [DANGEROUS] is in the open position there is still power and energy when racking the breaker and ppe must be used or remotely racked. We had it wrong thinking we were safe remotely opening the breaker then racking.

 

[zog]

But there are shutters that automatically move into position covering the live stationary contacts so you would have to be totally inept and it would have to be intentional to defeat the shutters in order to come into contact with the energized stabs. {/quote]

Likely not, shutters have been common in MV appliacations for years but not so much on LV gear and not with DS breakers as the OP mentioned he has.

 

[bure961]

That's correct we don't see any shutters inside the cb cell but we do see the fingers on the back of the cb that look like they attach to the bars or stabs in the rear of the cell. hmy:There is one cell with out a breaker in it.