OT(?) - NFPA70e recommmendations

Not sure if this is a legal topic for this forum but wasn't sure where else to post. I'm sure there are a few opinions out there.

The situation is a directive from our new safety manager that NFPA70e shall strictly be adhered to and no one is to be exposure to any live circuits greater than 50 V at our US plant. Period, no exceptions, even if appropriate PPE gloves are worn. Any probing required to troubleshoot circuits must be done by attaching probe point while the circuit is deenergized and the energize. The main panel I'm currently working on is completely IP20 rated, mainly 24VDC, and some 120VAC (fused at 10A)mainly for some NEMA 4 and 5 contactors that are being reused from an older facility that was recently decommissioned.

As can be expected, this takes a lot of time as you set up for five minutes for making a measurement that takes only 10 seconds. I have not read NFPA70e but I have heard that probing may be allowed in limited cases. What have your experiences been/ what guidelines do you follow? I hope to get a copy of standard next week.

NFPA70 E Standards for Electrical Safety Requirements for Employee Workplace.

What you have stated is not exactly what NFPA70E states.

One of the first things Part 2 Safety-Related Work Practices REQUIRES is training...Part II Chapter 1 Paragraph 5.

The training explains in better detail because there are many ussues involved....arc flash, movement of components, non electrical energy sources.

What it boils down to is guidelines and procedures to maintain a safe work environment. Its impossible to state that you are going to use NFPA70E without training people to understand the rules.

NOTE: Part II Chapter 4 Paragraph 1 Test Instruments and Equipment use: Only qualified persons shall perform testing on or near live parts operating at 50 volts or more.

It is admissible to test or check a system that is live.

I have been starting to hear noises about 70E from our customers. There have been recent changes to the standard that sound like what you said. I haven't been able to get to the bottom of it, yet, either.

We've implemented alot of what's in 70E at our facilities.

The only real big change is wearing the PPE while making measurements.

Rsdoran is right. You need training on how to use the PPE, when to use it, and why you use it.

You also should do an arc flash study in your plant to determine how much PPE is needed. Its not absolutely necessary but helps a whole lot.

The only other thing that is a pain is we cannot open a panel that has any energized wiring inside. Even if only the three barely exposed lugs at the top of the main CB are energized. We use a disconnect on the outside of all our panels as a lockout point.

Thanks for the responses.

We basically have a rule of thumb that anything over 230V and 30A has the possibility arc flash so we also do not open any boxes with power to the top of the fuses, circuit breakers, etc. The example we were given in training is how do you know there isn't dust, dirt, miscellaneous pieces of metal, etc. that might make continuity by the action of opening the door.

I've seen arc flash once that came off a 100HP motor that had just started with the motor terminal nuts attached only finger tight. I was 6' away walking towards it and it was memorable once my ears quit ringing and the big purple spots in front of my eyes went away. Needless to say, I have the utmost respect for large quantities of electrical power that are uncontrolled.

The case I outlined is basically just 10 Amps of 120 Volts that will pop the fast blow fuse that's installed to protect the circuit. I have not done the calculations but this seems to have a low potential for getting an electrical burn. I understand anything over about 50mA can stop the heart so that is why wearing gloves should provide protection. I also typically probe with just my right hand and keep my left hand away from touching anything so the ground path shouldn't pass down the left side of my body through the heart.

Another question: What's the maximum amps allowable below 50 V that you would be concerned with interms of "safety"?

Zero amps is pretty much my desired limit.

Electrical Safe Work Practice

Our plant is going the same way as the Big Three automakers, UAW, ect. with the limit of 50V and lots of PPE. It'll put a whole new twist to troubleshooting and downtime.

As a side note, you might not want to do this:
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At least he's wearing proper eye protection!