PPE within Substations

[zrjohnso]

I am performing arc flash calculations on substation equipment for 4kV, 12kV, and 25kV systems. Does anyone have an answer/opinion on wearing appropriate arc flash protection for opening circuit breaker doors to verify equipment name plates or to view relay settings on either electromechanical or electronic relays? Further, what about viewing AC panel circuit breakers for station service, or checking/changing Voltage Regulator settings?

It doesn't make since to me that personnel should have to wear moon suits or de-energize equipment to inspect ratings and settings, as some calculated results would suggest. Do those situations count as "exposed live parts?" Should the PPE requirements apply here? What do you think?

 

[mivey]

Probably sad to say but hardhat is usually all the protective gear I have on.

Zog, where you at man?

 

[realolman]

I'm not sure how you could even be in a substation, without having to wear ppe.

 

[mivey]

With a key.

[edit: That was flippant, but I came up old school and should mend my ways]

 

[ironman3452]

its a requriment when we open any panel, bucket, or any part that is energized

 

[jim dungar]

I am performing arc flash calculations on substation equipment for 4kV, 12kV, and 25kV systems. Does anyone have an answer/opinion on wearing appropriate arc flash protection for opening circuit breaker doors to verify equipment name plates or to view relay settings on either electromechanical or electronic relays? Further, what about viewing AC panel circuit breakers for station service, or checking/changing Voltage Regulator settings?

It doesn't make since to me that personnel should have to wear moon suits or de-energize equipment to inspect ratings and settings, as some calculated results would suggest. Do those situations count as "exposed live parts?" Should the PPE requirements apply here? What do you think?

The proper PPE should always be worn. What if the breaker decides to unsuccessfully operate while you have the door open checking its nameplate?

You may need to clarify your term substation? Is this an open air switch yard with individual outdoor breakers? Are the breakers in a lineup and installed in a block house/building? Is this equipment indoors in an industrial plant?

One issue I have noticed with open air substations is the working distance where the incident energy is calculated. Most people that enter open air switch yards are further away than 36" from energized parts. We often provide a table with multiple distance calculations for this reason (i.e. when operating a gang switch the operator is rarely closer than 120" to the live parts).

 

[zog]

I am performing arc flash calculations on substation equipment for 4kV, 12kV, and 25kV systems. Does anyone have an answer/opinion on wearing appropriate arc flash protection for opening circuit breaker doors to verify equipment name plates or to view relay settings on either electromechanical or electronic relays? Further, what about viewing AC panel circuit breakers for station service, or checking/changing Voltage Regulator settings?

It doesn't make since to me that personnel should have to wear moon suits or de-energize equipment to inspect ratings and settings, as some calculated results would suggest. Do those situations count as "exposed live parts?" Should the PPE requirements apply here? What do you think?

Sorry, been on vacation. You should be using the tables in the 70E for this, that is exactly what they were intended for. And yes you do need to wear PPE for these types of tasks but it is less than is required for other tasks on the same equipment, risk and proximity to the live parts is assumed to be less of a danger. The PPE requirements are supposed to be used whenever you "Interact" with the equipment (Will be clarified in 2009 70E), so opening a breaker door is interacting (Remmember some doors have interlocks that will trip the breaker, usually 70's vintage Westinghouse), but just looking at relay settings, no I would say no PPE besides the OSHA required non meltable fabrics found in 1910.269.

 

[zrjohnso]

Zog, can you expand more on why you think "no PPE besides the OSHA required non meltable fabrics found in 1910.269" for reading relay settings off a breaker? You seem to be the only one to think this way.

I think its a little excessive to wear a multilayer flash suit hood, jacket, pants, etc. to just cycle through some electronic relay settings. For arguments sake, lets assume I can't lower my HRC below a 4 even at the working distance of opening the breaker door and reading the relay. I understand accidents can always happen, but it doesn't seem like there's too great of a risk here.

 

[zog]

IF you fall withing the limits of the tables you can use the PPE requirements in table 130.7(C)(9)(A).

Each of your senarios requires different PPE, and relays on MV switchgear is typically not behind the breaker door but rather they are switchboard mounted, so it would be the same as "Reading a panel meter while operating a meter switch" in the 1kV and above MC SWGR section.

Of course you need to know if the tables can be applied, maybe your employer decided it is better to have overkill for PPE than to properly train the employees to make the proper PPE decisions.

 

[zrjohnso]

Thanks zog. Wasn't sure if that counted as "Reading a panel meter while operating a meter switch" since there is a hinged cover, and the equipment is energized.

By the way, how were the categories determined per operation within these tables? And what does "insulated cable examination, in open area" refer to exactly?

 

[zog]

Thanks zog. Wasn't sure if that counted as "Reading a panel meter while operating a meter switch" since there is a hinged cover, and the equipment is energized.

By the way, how were the categories determined per operation within these tables? And what does "insulated cable examination, in open area" refer to exactly?

Well, the OSHA guy in your region makes the call on that, but thats the way it was explained to me by the 70E commitee chairman and current OSHA electrical guy in the NE region.

Each type of task in the tables had different assumed working distances, as far as the cables go, sounds pretty self explanatory to me, MV cables are typically on the roofs of industrial plants and thier jackets and sheilds need to be inspected on a regular basis.