We are installing a new maintenance mode switch on a gear and I was asked if while in maintenance mode, could they use different level PPE that is dependent on the switch being activated. My first thought was yes, as part of the JSA or maintenance procedure they could verify its in Maintenance mode and then proceed based on the lower IEs. That would mean two different stickers on this gear however and could cause confusion.

How do most people handle this? Is the maintenance mode just a mitigation device and still require worst case PPE or have two different levels of PPE for each gear? any literature to back this up?

Be careful w/ ERMS switches (or ARMS, etc.), especially on gear that does not have barriers between sections and you are exercising breakers in the same lineup.
Example: turn down ERMS on main, then switch off a feeder breaker in the same gear. IMHO, in this example, if the gear has no barriers, the ERMS is essentially worthless. We have EMRS switches installed on mains in switchboards and the electricians think they are good to use it and not don the "bomb suits". So, it's a battle to get them to understand how the gear is constructed and think before they act.
W/ regards to multiple labels, I think it best to label w/ the normal operating mode. ERMS switch use should be in a MOP and the AFIE documented that way. Helps avoid confusion...

Mike

My customers usually put a single 'worst case' label on the equipment. They kept the maintenance switch values with the report. A person qualified to implement the maintenance switch would know where to go to find the appropriate PPE.

I agree.

I would label with worst case operating incident energy level only. Use arc flash maintenance switch as an additional layer of arc flash reduction, even with the worst case PPE being used.

Too much PPE can cause a safety problem, such as limiting visibility, movement, and causing heat stress. Worst case might end up being worse.

What you may want to consider is as part of your in-house roll out training, I am sure that you are instructing your workers on how to read and interpret your detailed warning labels for arc flash and shock. As part of this, explain the ARMS and briefly what it does in mitigating the IE. From there, explain the label and how the IE rating is less when the ARMS is engaged versus not engaged. I think that you may find this is a good exercize for them. I hope that this helps

We use maintenance mode on switch gear breakers to reduce incidence energy on downstream MCC units typically. We have a dual label for that purpose. That way they have an option ask to what PPE level to wear based on using maintenance mode or not. We do recommend using maintenance mode when doing any activity at the MCC including switching disconnects.

One other thing to remember about ERMS/ARMS/etc.: if you have large motor loads that cycle on/off, be careful as the inrush could trip off a breaker that you don't want opened!

Mike

I've noticed that oftentimes the maintenance mode setting is of no labeling benefit because the arcing current is already in the instantaneous region of the breaker curve.

It might be of some practical benefit if the actual arcing current from a real event is lower than the calculated value, if the actual real world current was in the maintenance mode instantaneous band but not in the normal mode band.