Working in a live panel but de-energized conductors.

[Dan Kissel]

We have control panels that are common to the operation of our entire facilities. If we LOTO those panels to do work in them, we might as well send everybody home because the plant is down and half of our in process product would be lost. We can shut down the control panel without introducing additional hazards or increased risk. (Except if you consider closing the plant an increased risk)

I am looking for interpretation of NFPA 70E 130.2 A Energized work. Can I work in an energized control panel if I have PPE on as long as the conductors that I interface with are in an ESWC. Essentially I can trip the circuit breaker (no LOTO on CB) in a live panel to make the conductors to a relay or VFD dead, replace the panel component and then re-energize.

The panel would be energized, PPE on, work permit filled out (would it be needed) - am I code compliant?

 

[petersonra]

We have control panels that are common to the operation of our entire facilities. If we LOTO those panels to do work in them, we might as well send everybody home because the plant is down and half of our in process product would be lost. We can shut down the control panel without introducing additional hazards or increased risk. (Except if you consider closing the plant an increased risk)

I am looking for interpretation of NFPA 70E 130.2 A Energized work. Can I work in an energized control panel if I have PPE on as long as the conductors that I interface with are in an ESWC. Essentially I can trip the circuit breaker (no LOTO on CB) in a live panel to make the conductors to a relay or VFD dead, replace the panel component and then re-energize.

The panel would be energized, PPE on, work permit filled out (would it be needed) - am I code compliant?

I think you could probably do so. It would probably involve considerable redesign of the control panel.

The standard does not actually require that you de-energize anything. Only that the exposure to the employee be removed. In any case, if what you are working on is in an ESWC why would you need PPE? by the way, you can't claim something is electrically safe if something 2 inches away is not.

 

[jtinge]

Your proximity to exposed energized circuit parts while you are working on parts in an electrically safe work condition will determine whether or not shock hazard PPE is required. If you are within the shock approach boundaries for the exposed energized parts, shock hazard PPE will be required, (NFPA 70E 2015, 130.4).

 

[Dan Kissel]

Your proximity to exposed energized circuit parts while you are working on parts in an electrically safe work condition will determine whether or not shock hazard PPE is required. If you are within the shock approach boundaries for the exposed energized parts, shock hazard PPE will be required, (NFPA 70E 2015, 130.4).

PPE is required if you work inside the boundary but code says that you can work inside the boundary only if de-energizing increase a hazard or risk, otherwise - de-energize!

My question is de-energize what? Can only the conductors to the failed device be de-energized or must the panel be de-energized?

 

[Jraef]

From an Arc Flash hazard risk standpoint (different from the risk of shock), once the door is open and there is anything live in that box, you are exposed to the danger, so your PPE is required.

The ESWC issue is separate and you CAN be in the vicinity of live conductors as long as you can't touch them. Hence, line terminal barriers for main disconnects and breakers. So for example there are some MCCs available now that remove the stabs from the bus while the door is still closed, so the bucket is in an ESWC once you have done your Test - Verify - Test procedure and you can open the door to work on it, or (better yet) remove it to work on it on the bench. But you are NOT allowed to be working in that bucket with the door open without being suited up with the proper PPE for the Arc Flash risk exposure. An event could happen somewhere else in that MCC and the blast energy will go to the least restrictive area, your open door.

 

[Dan Kissel]

PPE is necessary to work in a live panel. I get that. 70E says that I can do energized work ( with PPE on is a given) only if de- energizing would cause additional hazards. De-energize what?
The question is "Can I de-energize the specific conductors that I intend on working on inside the control panel while keeping the rest of the panel energized?" The panels have 480 vac power next to 120 vac relays, all within inches of each other. (typical control panel) The only LOTO is for the entire panel.

70E 130.2 Energized electrical conductors and circuit parts shall be put into an electrically safe work condition before an employee performs any work if any of the following conditions exist: employee is within the limited approach boundary (1 foot for 230 and 480 vac).

I do not intend on working on live conductors but certainly within 1 foot of live conductors.

Am I correct that I can work inside a live panel but not on live conductors with proper PPE. Live conductor is a XXX AWG THHN wire.