NFPA 79 - wire nuts not suitable for motor connections ?
NFPA 79 - wire nuts not suitable for motor connections ?
(OP)
In NFPA 79-2007, Clause 13.5.9.2 states, "Electrical connections at motor terminal boxes shall be made with an identified method of connection. Twist-on wire connections shall not be used for this purpose."
What I think this means that wire nuts cannot be used in motor 'peckerheads'. Other than European (CE-Marked) motors, I've never seen anything other than wire nuts with or without electrical tape wrap for making these connections.
Which US motor manufacturers offer terminal strips or connecting studs in the peckerhead?
Alternately, what "identified" methods exist for this conection? I'm having difficulty finding suitable connectors that won't cost a fortune to implement, or that will fit three into a typical peckerhead.
Thank you.





RE: NFPA 79 - wire nuts not suitable for motor connections ?
The last time I had to to the installation of a sizable number of 480-volt motors, we used ring terminals on all the leads, and connected the rings together with appropriately sized nuts and bolts or screws, and then taped the connections over.
Again it was a given fact that some people could mess up this installation.
On some larger motors, I've seen cable to cable connections made with split-bolts.
In any method, a high level of care is needed to produce satisfactory results.
old field guy
RE: NFPA 79 - wire nuts not suitable for motor connections ?
There are crimp-on connectors that look a lot like wire nuts, perhaps that's what you've seen in those motors? But more likely, your electricians are no more familiar with this requirement than I was -- or maybe they've heard the requirement but think they're smarter than the NFPA.....
RE: NFPA 79 - wire nuts not suitable for motor connections ?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
Since my original post, I've come across a couple of commercially-available alternatives to wiring nuts:
http://
http://www-public.tnb.com/ps/endeca/index.cgi
These type connectors takes the skill out of the terminations that oldfieldguy referred to.
I've also seen some 1000V shrink-wrap mat'l that can be used over the ring terminals bolted together. I wonder if I can replace the whole taping routine with this.
http
Thanks again.
Bob Steele
Electrical Designer
www.gala-industries.com
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I use the GelCaps when I can, they work great and are cost effective compared to using tape. The only problem is that they are too big for small motors.
Don
RE: NFPA 79 - wire nuts not suitable for motor connections ?
Just remember that you can't make things foolproof... fools are on a program of continuous innovation and improvement...
there are many methods of connection that will work well iff applied carefully by knowledgeable people. No method will work if applied carelessly...
good luck!
old field guy
RE: NFPA 79 - wire nuts not suitable for motor connections ?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
From a practical standpoint, motor terminal boxes are subject to a lot of vibration that normal junction boxes are not subject to, so it makes sense that tougher standards might apply to motor terminals.
Wire nuts are generally not a good choice for stranded wiring, in any application.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
That may or may not be the case... but they are certainly THE standard choice for many many applications -- in fact, you most likely have some in your very own home, unless you personally installed or inspected inspected each and every splice.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
But I have never EVER seen a qualified industrial electrician use wire nuts unless on anything that requires 14ga wire or greater, unless it was a temporary test or emergency restart situation where they knew they were going to come back and do it right when they had time. Industrial applications are typically subjected to more vibration, modification and exposure to corrosive influences than anything you will see in a residential location.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I have very little stranded wire in my house, and certainly use wire nuts at home when the need arises.
I usually don't consider residential work in this forum.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
When I look at a motor manufacturers website I do not see recommended ways on termination in their peckerhead?
Why is this the case?
Can anyone give me an example where the motor manufacturer has recommended this or that based on the above code?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I don't know about commerical building wiring.
I know for sure at our industrial plant the electricians never use wire nuts.
If you think about what prevents the wire nut from untwisting, it seems like it's not a lot. I guess there is some kind of friction device inside that clamps to the conductors... to be honest I don't know how it works. From that perspective, a bolted connection certainly seems preferable.
Strange that we consider various machinery where we work to be critical, but we don't consider the connections in the wall where our familiy sleeps to be as critical?
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RE: NFPA 79 - wire nuts not suitable for motor connections ?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
You seem to be correct, electricpete. Per NFPA 79 1.3.2: "This standard shall not apply to the following: ... (2) Machines used in dwelling units"
RE: NFPA 79 - wire nuts not suitable for motor connections ?
One of the top results is an article discussing all the fires experienced at one facility until they stopped using wire nuts, and the question was posted what others thought of wire nuts and other options.
There doesn't seem to be much general awareness of NFPA 79 13.5.9.2.
It's a shame that this requirement is not repeated in the NEC (NFPA sure repeats plenty of other stuff), that would probably lead to much greater compliance (and fewer fires).
RE: NFPA 79 - wire nuts not suitable for motor connections ?
Regarding: "Is it possible that wire nuts are not allowed is that the motor wiring is stranded and the electrical service is solid core. I beleive that wire nuts woud be terrible for a solid/stranded appliciation."
As electricpete said, his ceiling fan came with wirenuts in the box -- most any electrical equipment (lamps, fans, etc) you buy from Home Depot or Lowe's will come with wire nuts in the box. I realize that most industrial plants don't buy their stuff from HD.... but the question is not regarding industry standard but rather code requirements.
Presumably HD's vendors realize that most people have #14-#12 solid wire in their homes, but apparently they have no issue with the use of wire nuts (not just any wire nuts either... those are the cheapest smallest no-spring 100%-plastic nuts you will find anywhere on the planet). So presumably it is OK to use wire nuts for stranded/solid connections.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I don't think any of this is an NEC violation provided the wire nuts are listed for use with stranded and/or solid wire of the appropriate sizes and quantities. If you look on a box of wire nuts, it will have a table of acceptable use and the combinations of wires (stranded or solid) that can be used.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I also saw the "his ceiling fan came with wirenuts in the box" and I thought , "Gee, if it shipped from China that way, it must be OK."
Many years ago (when vacuum tubes were popular), solid core wire was twisted together (about ten twists) then rubber insulation followed by tape. When I first saw wire nuts, I saw them as a quick way to insulate the twisted wire, not as a way of connecting the wires (and still do).
I find this thread most interesting because it deals with something fundamental in electrical work which may not be codified but is handed down by a verbal tradition. And may be wrong or misunderstood.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
The Underwriters Laboratories lists these type of connectors as pressure type. They are, there for, acceptable for use in all building classifications covered by NFPA 70 as Listed by UL. Their are two basic types of "wire nuts", live spring and fixed. It is important to know the difference.
I have used and have seen "wire nuts" used to make motor terminations in on conductors #10 and smaller as permitted by the code with great success.
Oldfieldguy, I absolutely agree with you. To paraphrase, no matter the materials or methods, if its done poorly by unqualified persons, you WILL get poor results.
Scope of NFPA 79: "Document Scope: 1.1* Scope. 1.1.1 The provisions of this standard shall apply to the electrical/electronic equipment, apparatus, or systems of industrial machines operating from a nominal voltage of 600 volts or less, and commencing at the point of connection of the supply to the electrical equipment of the machine. 1.1.2 This standard shall not include the additional requirements for machines intended for use in hazardous (classified) locations."
Scope of NFPA 70: "Document Scope: (A) Covered. This Code covers the installation of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways for the following: (1) Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings (2) Yards, lots, parking lots, carnivals, and industrial substations FPN to (2): For additional information concerning such installations in an industrial or multibuilding complex, see ANSI C2-2002, National Electrical Safety Code. (3) Installations of conductors and equipment that connect to the supply of electricity (4) Installations used by the electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings, that are not an integral part of a generating plant, substation, or control center. (B) Not Covered. This Code does not cover the following: (1) Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles FPN: Although the scope of this Code indicates that the Code does not cover installations in ships, portions of this Code are incorporated by reference into Title 46, Code of Federal Regulations, Parts 110-113. (2) Installations underground in mines and self-propelled mobile surface mining machinery and its attendant electrical trailing cable (3) Installations of railways for generation, transformation, transmission, or distribution of power used exclusively for operation of rolling stock or installations used exclusively for signaling and communications purposes (4) Installations of communications equipment under the exclusive control of communications utilities located outdoors or in building spaces used exclusively for such installations (5) Installations under the exclusive control of an electric utility where such installations a. Consist of service drops or service laterals, and associated metering, or b. Are located in legally established easements, rights-of-way, or by other agreements either designated by or recognized by public service commissions, utility commissions, or other regulatory agencies having jurisdiction for such installations, or c. Are on property owned or leased by the electric utility for the purpose of communications, metering, generation, control, transformation, transmission, or distribution of electric energy. FPN to (4) and (5): Examples of utilities may include those entities that are typically designated or recognized by governmental law or regulation by public service/utility commissions and that install, operate, and maintain electric supply (such as generation, transmission, or distribution systems) or communication systems (such as telephone, CATV, Internet, satellite, or data services). Utilities may be subject to compliance with codes and standards covering their regulated activities as adopted under governmental law or regulation. Additional information can be found through consultation with the appropriate governmental bodies, such as state regulatory commissions, Federal Energy Regulatory Commission, and Federal Communications Commission. (C) Special Permission. The authority having jurisdiction for enforcing this Code may grant exception for the installation of conductors and equipment that are not under the exclusive control of the electric utilities and are used to connect the electric utility supply system to the service-entrance conductors of the premises served, provided such installations are outside a building or terminate immediately inside a building wall."
RE: NFPA 79 - wire nuts not suitable for motor connections ?
NFPA 79 seems to state that wire nuts shall not be used for motors (except in residential applications). However, you seem to indicate that wire nuts are just fine for any motor conductor #10 AWG or smaller, residential, commercial, industrial, amusement park, whatever.
Are you stating that NFPA 79 is not applicable? Or have I somehow misunderstood you?
RE: NFPA 79 - wire nuts not suitable for motor connections ?
On a different note I have seen contactors,lugs and just about everything else that a wire can terminate to fail because someone hasn't stripped the insulation back far enough.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
Where there are differences or conflicts between the two, the NFPA 79 Standard applies over the NEC, again as far as machinery is concerned.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
The NEC says that all connections are to be mechanically sound etc etc.
A LONG time ago Dad taught me to twist the wires together (solid) then solder then tape and stuff in box. That was standard then - plastic tape had just come on the market so had Romex now called NM.
Since then as a working electrician (US Navy, Trojan Nuclear plant etc etc) I have used all methods wire nuts, crimp connectors, burndy (split bolt etc etc), cad weld, solder, terminals with nuts and bolts on anything up to 12,500 volt and 250 VDC submarine battery.
I have found that with a minimum of 4 twists with pliers then wire nuts there have been very few problems. This includes stranded onto solid. BUT you cannot be cheap with wire you need to strip about half inch for orange MINIMUM and more length if more conductors. If stranded onto solid I strip small stranded one inch to get sufficient mechanical strength.
As far as water NOTHING works to keep it out. Scotch cast is about the only thing. Noalox on the conductors works well to keep the oxidation down - even works well on my truck battery terminals.
Oh yes for crimped connections I use a Greenlee crimper not that Home Depot trash.
Dan Bentler
RE: NFPA 79 - wire nuts not suitable for motor connections ?
"wirenuts" work fine where connecting 2 or 3 wires #18 to about #14, but aren't a good choice for a motor (or other machinery) that is expected to stay connected "permanently", or subjected to any substantial amount of heat, vibration, moisture. "split-bolts" and crimp type terminals connected with nuts and bolts (machine screws) are both strong, durable and reliable connections. Properly taped connections are imperative for both insulating and mechanical characteristics, and facilitate testing or replacement far better than heat-shrink etc.
Exclusion of moisture is not a problem related to taping or heat-shrinking, but is most difficult to deal with if there is moisture in the wire/cables.
"cost a fortune" catches my attention and suspicions; if you are not responsible for proper functioning, operation or maintenance of the motors you'll get affordable connections with wirenuts or even tape.
If there's one peeve of mine and seemingly most electricians/mechanics it's the small size of "peckerheads" on motors. The term comes from the intelligence / mentality of the manufacturers that produce them and the engineers that design things they never have to work on under typical conditions of service.
And yeah, some of 'em even hang-around eng-tips from time to time and will take offense from my remarks.
Please let us all know how this works out for you! and don't forget FAQ731-376: Eng-Tips.com Forum Policies
RE: NFPA 79 - wire nuts not suitable for motor connections ?
If there's one peeve of mine and seemingly most electricians/mechanics it's the small size of "peckerheads" on motors. The term comes from the intelligence / mentality of the manufacturers that produce them and the engineers that design things they never have to work on under typical conditions of service.
UNQUOTE
In the Navy the boxes often had a short 90 conduit coming out. Supposedly this is the source of pecker head. Seems reasonable a lot of sailors I knew dreamed up terms like this.
On the other hand I like the version I just quoted. I have sworn vile oaths at design engineers and management for making things too small or just inaccessible. Peckerheads is the most common. I have always wondered do they get a percentage of the yearly savings in metal from making things so damn small or just inaccessible.
OR is the other rumor true that they have a Dept of Frustration whose only task is to make life tough on maintenance guys?
Funny yet true story. Knew a licensed construciton electrician. He was wiring his home and I commented that I did not often see the constuction guys I had worked with twisting the conductors together before placing the wire nut. Chris replied "at work I don't they don't allow us the time. But this is MY house and I want it done right"
Dan Bentler
RE: NFPA 79 - wire nuts not suitable for motor connections ?
In the past have used wire nuts in peckerhead and have not had problems as described above, of course that all goes back to proper installation.
I did notice on my last big job for motor terminations, parcel carrier distribution center, that the customer specifically requested a collared system with a set screw clamp for the motor termination. But the plastic collar that was used to insulate the termination was not installed right about 50% of the time. Of course this caused overloads to no end until a proper install was done.
To me I think the wire nut was abused to no end due to inproper installation, to me that is why its now not proper in motor terminations in the peckerhead.
I know that some electrical installers use terminal strips in junction boxes instead of the wire nuts. I have seen enough bad splices caused by wire nuts to see the point of using terminal strips as the proper method.
RE: NFPA 79 - wire nuts not suitable for motor connections ?
I wanted to illuminate the conflict between NFPA 70 and 79. The question left unanswered would be; which one takes precedence?
If I were building a machine that fell with-in the scope of NFPA 79 and was to have an electric motor as an integral part of the process, then I would follow the standards of NFPA 79 and not use "wire nuts" to terminate the motor leads no matter the conductor size.
If I were working with-in one of the building classifications that fell with-in the scope of NFPA 70 and asked to terminate an electric motor that was NOT an integral part of a machine, then I would have no personnel issues in utilizing "wire nuts" to do so (provided the conductors are #10 or smaller).
RE: NFPA 79 - wire nuts not suitable for motor connections ?
http://www.wago.us/products/325.htm
However keep in mind wire end ferrules need to be used with this some of these products.
http:
RE: NFPA 79 - wire nuts not suitable for motor connections ?
steelerr
http://so
RE: NFPA 79 - wire nuts not suitable for motor connections ?
For up to (2) AWG 10, Panduit JN314-412
http://
For smaller wires in the motor termination box, Panduit JN218-216
http://
For larger than AWG 10, Burndy Uni-Tap connectors
h
Again, thanks for your interest and participation