Hello All,

I'm working on the FEED stage for a new compression facility. I'm getting a suggestion for a change based on past history with Arc Flash issues.

Specifically in the past the station control system PC monitors have been located in the Electrical/Control building. Basically a self framing type building. The building contains the 600V MCC's, various control panels, etc... The monitors would have been against a wall probably 2 or 3 meters from the edge of the MCC.

I believe based on an arc flash study they have that they now want to locate these monitors in a different building. I think there are concerns about PPE what they have to wear just to be in the same area as the MCC's.

My question is: If I were to design the skid with a partition between the MCC area and the controls area would that mitigate any arc flash concerns related to being in the controls area without arc flash specific PPE?

Thanks in advance,

Rob Simpson.

there is nothing in 70E which discusses a blast energy sufficient to take down a wall.

Just being in an MCC room does not necessitate arc flash clothing unless there is significant energy being switch, ie switchgear. MCC's and panelboards do not routinely fit this definition. So if all doors are closed and there are no exposed live parts, there is no HRC clothing required.

If you wall was non-permeable and of reasonable integrity and would sufficient deflect or withstand the highest arc fault, then a wall might work.

You could argue that using the station control system to operate the MCC is interacting with the MCC. Then you would need to be outside the arc hazard boundary to be without PPE.

Prudence would dictate locating the controls outside the boundary if an operator is at the PC monitor for long periods of time, regardless of whether the MCC is controlled at the monitor location. Operation of starters or breakers by others would require the operator to move away from the MCC.

Thanks for the info gents.

I got a bit more info from the site.

It is only standard PPE that is called for to be in the MCC room. On this site there are living quarters so they don't want to put regular PPE on to interact with the control system. It seems a partion would do the trick but I'm going to relocate the equipment as that will keep them happier.

Thanks again for the insight on the partition. I will keep that info in my back pocket.