Indicator Lights for Motor "energized/non-energized status"

[ACinstructor]

In a recent Motor Control class that I teach, the question of if the NEC had provisions for indicator lights to be installed to show if a motor control system is energized or not energized. Some students indicated that their work places required red lights to indicate a motor circuit is energized and green that it was non-energized and safe to approach and work on. I have not been able to find any definitive proof if that is proper or not. Any help will be appreciated.

 

[GoldDigger]

There is a serious problem with a light to indicate un-energized. Actually two.
The green light will have to get power from somewhere and could just indicate the position of a possibly broken contactor. (It may not even tell you that the machinery could not be remotely energized at any time.)
And it is in no way a substitute for a locked disconnect and contact voltage testing. It could lead to a false sense of security.

Tapatalk!

 

[petersonra]

In a recent Motor Control class that I teach, the question of if the NEC had provisions for indicator lights to be installed to show if a motor control system is energized or not energized. Some students indicated that their work places required red lights to indicate a motor circuit is energized and green that it was non-energized and safe to approach and work on. I have not been able to find any definitive proof if that is proper or not. Any help will be appreciated.

Some of our customers use red=on green=off, while others use red=off and green=on.

The NEMA standard was red=on, green=off.

I don't believe the NEC has any such requirements. In fact, the NEC does not require indicator lights on motors at all.

under no circumstances is a light on its own adequate proof that it is safe to do anything.

 

[jim dungar]

The NEMA standard was red=on, green=off.

Back in the 1980's, there was no consensus as to which color meant what. Square D was Red=Run and Cutler Hammer (?) was Green = Run. I know we had to be careful of the specification requirements as we had a price adder and delivery delay for the other color.

Since that time, color coding per NFPA79 has become more common.

 

[don_resqcapt19]

Back in the 1980's, there was no consensus as to which color meant what. Square D was Red=Run and Cutler Hammer (?) was Green = Run. I know we had to be careful of the specification requirements as we had a price adder and delivery delay for the other color.

Since that time, color coding per NFPA79 has become more common.

I am sure if I saw a quote for an adder and delivery delay for that change I would just look for another brand of equipment

I mean how hard is it to move the colored lens from one pilot light to the other?

 

[ritelec]

Know notta...............
but to me, seams there should be something else about position or something for our color blind (challenged) friends???

 

[jim dungar]

I mean how hard is it to move the colored lens from one pilot light to the other?

Hey I, argued with it back then too.
In reality this was rarely a big deal, very few consultants paid attention to what was in their boiler plate specifications, they just wanted 'lights'.

The primary problem was with motor control centers and their off-the-shelf drawing packages for quick lead times. Any thing non-standard required manual procedures be followed.

Don't you remember the problems with ordering a new car versus buying one off-the-lot?

 

[don_resqcapt19]

Hey I, argued with it back then too.
In reality this was rarely a big deal, very few consultants paid attention to what was in their boiler plate specifications, they just wanted 'lights'.

The primary problem was with motor control centers and their off-the-shelf drawing packages for quick lead times. Any thing non-standard required manual procedures be followed.

Don't you remember the problems with ordering a new car versus buying one off-the-lot?

I know. It is just that little things like that that could be easily fixed in the name of customer service and aren't bother me.

 

[petersonra]

I am sure if I saw a quote for an adder and delivery delay for that change I would just look for another brand of equipment

I mean how hard is it to move the colored lens from one pilot light to the other?

Where I used to work we bought a fair number of AB MCCs.

If you ordered them with red = on it was a standard thing.

To get green = on cost extra money and time.

We generally bought them with red lights and if a customer had spec'd green = on, we changed the color caps.

 

[Jraef]

Where I used to work we bought a fair number of AB MCCs.

If you ordered them with red = on it was a standard thing.

To get green = on cost extra money and time.

We generally bought them with red lights and if a customer had spec'd green = on, we changed the color caps.

Still that way. No extra charge actually, but it does change the status from "Quick Ship" to "Pre-Engineered". The difference is, for Quick-Ship, no engineers touch the order, everything is spit out of a machine. If you change anything from the QS program, someone has to tell the factory to make the change. It doesn't cost any more to do that, but it means someone in Engineering has to touch the order, which means getting in line with all the other orders that need to be touched. However if there is ANYTHING else about your order that means it needs to be touched by an Engineer, then changing lens colors is irrelevant to both cost or lead time.

It is not cheaper, but often FASTER, to get the lenses and change them in the field. I used to do it all the time, but the advent of LED pilot lights has changed that now. A Red LED PL comes with a Red LED, a Green PL with a Green LED. If you put a red lens on a green LED, you get brown...

Pilot light colors for most mfrs follow the NFPA 79 standards, which were originally derived from the old JIC standards. Red = Power applied, dangerous conditions, Green = Ready, available, but not running. They haven't changed in decades, but not everyone subscribes to the idea that those standards apply to them. I've been having this same discussion for 30+ years, this is a debate that will never end,