"NFPA 79, Electrical standard for Industrial Machinery"

[milmat1]

"NFPA 79 Electrical Standards for Industrial Machinery"

What exactly is this and how does it differ from NFPA / NEC regulations?

I have always understood that machinery designers did not have to adhere to the NEC unless of course they were claiming some certifications, or claiming to be "Listed"...

Anyone shed some light on these issues.. Or add some thought ?

 

[petersonra]

this is a voluntary standard, often used as the bare minimum specification for industrial machinery. it would be something that would be contractually agreed to between a buyer and a seller, as opposed to being mandated by some governmental entity as the NEC often is mandated.

Listed has nothing to do with complying with the NEC.

While it is certainly true that the machinery itself is not covered by the NEC, as a practical matter it has to accommodate NEC requirements. This is often a misunderstood distinction.

For instance, the NEC requires motors have short circuit and overload protection, and disconnecting means. If those functions are supplied as part of the machinery itself, it would have to comply with the NEC requirements for such things. However, you could also design a machine that did not supply any of that and force the end user to supply it.

 

[iwire]

this is a voluntary standard,

Maybe voluntary but choosing to ignore it may result in OSHA citations under the general duty clause


http://en.m.wikipedia.org/wiki/General_duty_clause

 

[petersonra]

Maybe voluntary but choosing to ignore it may result in OSHA citations under the general duty clause


http://en.m.wikipedia.org/wiki/General_duty_clause

has that ever actually happened?

 

[milmat1]

Thank you for the clarification, I (we) design our equipment and the control panels to be certain the customer can comply with the NEC when he makes his connections etc.
As for directly following the Code, I try to comply simply because in most cases it's good practice to do so. However I don't sweat much if I step out of bounds a little.
However there are customers who specify in the contract that the equipment meets certain standards. So then I will be much more diligent.

 

[iwire]

has that ever actually happened?

You are asking if OSHA handed out fines under the general duty clause?


I have no facts at hand to support my opinion but I see that the same as asking if our taxes are spent recklessly.

I will see what I can find.

 

[iwire]

Ok in no time at all I found six citations in five years under the general duty clause referencing NFPA 79 and over 7,000 citations of the general duty clause overall. The time frame was 2010-2015.



https://www.osha.gov/pls/imis/Gener...&startday=10&startyear=2015&category=&InspNr=

 

[petersonra]

Ok in no time at all I found six citations in five years under the general duty clause referencing NFPA 79 and over 7,000 citations of the general duty clause overall. The time frame was 2010-2015.



https://www.osha.gov/pls/imis/Gener...&startday=10&startyear=2015&category=&InspNr=

none of these citations were for not following NFPA79. They were all for not having (operable) e-stops and just referenced NFPA79 as one way of complying with the requirement for estops.

 

[petersonra]

Thank you for the clarification, I (we) design our equipment and the control panels to be certain the customer can comply with the NEC when he makes his connections etc.
As for directly following the Code, I try to comply simply because in most cases it's good practice to do so. However I don't sweat much if I step out of bounds a little.
However there are customers who specify in the contract that the equipment meets certain standards. So then I will be much more diligent.

About 10 or maybe 15 years ago, the various code panels and UL modified NFPA79 and UL508a so they were "harmonized" with the NEC, and with each other. Prior to the harmonization there were a few things that both UL508a and NFPA79 allowed that were moderately dubious under the NEC (mostly having to do with conductor ampacity of larger conductors). I have not run across anything in current versions of UL508a or NFPA79 that conflict either with each other or the NEC. There may be something, but I can't recall any offhand.

 

[jim dungar]

I have not run across anything in current versions of UL508a or NFPA79 that conflict either with each other or the NEC. There may be something, but I can't recall any offhand.

I think one area is the 'color coding of conductors'.

 

[iwire]

none of these citations were for not following NFPA79. They were all for not having (operable) e-stops and just referenced NFPA79 as one way of complying with the requirement for estops.

That is how the general duty clause works ..... it is still a citation for not following NFPA 79 or another well accepted standard. I really do not understand the hair you are trying to split.

 

[petersonra]

I think one area is the 'color coding of conductors'.

I think you might be right wrt hot legs. Otherwise they are compatible.

 

[jim dungar]

I think you might be right wrt hot legs. Otherwise they are compatible.

I can usually tell when an 'electrician' has built a control panel, as all the 480V wiring is colored Brown Orange and Yellow however, NFPA79and UL508 would like to see all AC or DC line voltage done with black insulation, AC control done with red, and DC control in blue. Grounded and grounding conductor colors are the same across the standards.

 

[petersonra]

I can usually tell when an 'electrician' has built a control panel, as all the 480V wiring is colored Brown Orange and Yellow however, NFPA79and UL508 would like to see all AC or DC line voltage done with black insulation, AC control done with red, and DC control in blue. Grounded and grounding conductor colors are the same across the standards.

Wiring according to the color code in UL508a or NFPA79 is not incompatible with the NEC though. The code would allow for those colors to be used, while not mandating them.