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puckman

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ridgewood, n.j.
We are in the process of having a study . MY company feels as long as you have ppe on everything is fine even if the switchgear is rated at 40cal.
They want to open the rear of the metal switchgear 480v 4000amp. to get the size of the feeders going out to the mcc that are in different buildings . I informed them that all the sizes are on the online we have which are 25 years old. Also each feeder that lands in a mcc at a different location lands on a main cb for the mcc. My thinking is to work at a safer level and just open up the bucket door and record the sizes of the cables.
Does anyone have an opinion if this is a safer way to collect the cable sizes then opening the rear of the energized swichgear ? All cables leave the building underground to their locations. We will get their lenghts also.
Either the people doing the study labeled the switchgear work at hazard 4 or my company did.
Any imput would be helpful
 
puckman said:
We are in the process of having a study . MY company feels as long as you have ppe on everything is fine even if the switchgear is rated at 40cal.
They want to open the rear of the metal switchgear 480v 4000amp. to get the size of the feeders going out to the mcc that are in different buildings . I informed them that all the sizes are on the online we have which are 25 years old. Also each feeder that lands in a mcc at a different location lands on a main cb for the mcc. My thinking is to work at a safer level and just open up the bucket door and record the sizes of the cables.
Does anyone have an opinion if this is a safer way to collect the cable sizes then opening the rear of the energized swichgear ? All cables leave the building underground to their locations. We will get their lenghts also.
Either the people doing the study labeled the switchgear work at hazard 4 or my company did.
Any imput would be helpful
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  1. In general, opening the door of any piece of energized equipment puts you at maximum risk, so removing the rear plates of the switchgear is not really that different. But also, switchgear with rear access is not INTENDED to be opened when live, there are ZERO safeguards against touching live components as there would be if accessed properly. I think it is a very poor decision, you are at maximum risk, and you are maximizing the likelihood of creating an Arc Flash incident.
  2. If you say the information is on the drawings and it is correct, why are they questioning it?
  3. If the cables terminate at the other end on an MCC incomer, which likely has a shield over the conductors when the door is opened, why the heck can't they understand that the cable will be the same size at either end?
In my opinion, for what that's worth, they are unduly increasing the risk of a hazardous situation occurring when there are safer alternative availble. Tell them to run that up the flagpole with legal...
 
It is a judgement call. There are factors you have not covered.

How often has the 'metal switchgear' been maintained? If it has been opened and cleaned within the past month, I would give a different answer than if it has not been opened for 25yrs.

Are the MCC's in easily accessible areas, my last data collection project involved equipment on the floor of an operating food processing plant, while the feeder gear was in dedicated electrical rooms.

In general I try to reduce the number of devices I need to open (e.g. opening one hinged rear access panel versus having to remove covers on four MCC's).
 
Switchgear has not been addressed in anyway in atleast 10 years and mcc a little better.
Mcc has a bucket door and the cable insulation is visable. cables coming from switchgear .
Switchgear rear panels are not on a hinge , must remove bolts from left and right sides.

I feel going to each mcc and opening hinge cover to main cb is a much beeter and safer way to confirm cables.

1 mcc main cb for each switchgear breaker.
 
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