NFPA 79 - wire nuts not suitable for motor connections ? 5

[steelerr]

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.

 

[sreid]

Peebee,

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.

 

[MagneticFlux]

The current NFPA 70 (NEC) does address the use of "wire nuts" in Article 110.14. The term "wire nut" is trade slang.

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."

 

[peebee]

MagneticFlux -- Not quite sure I follow you.

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?

 

[nmark]

I have seen lots of wirenuts fail and in my experience water and other conductive materials fit nicely right next to the conductors.
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.

 

[steelerr]

Generally, the NFPA 79 Standard will take precedence over the NEC Code when it comes to machinery. If there is vague language in the Standard (and there are a few cases there), then the NEC is observed.

Where there are differences or conflicts between the two, the NFPA 79 Standard applies over the NEC, again as far as machinery is concerned.

 

[ssn596]

I find this most interesting. I would surmise that for 99% of small motors wire nuts are used. On my boat I replaced ALL factory wiring using exposed crimp splices with junction boxes and used wire nuts. In some cases I pulled in flex plastic conduit. The wire nuts do not comply with American Yacht requirements YET it is OK to have exposed butt splices?? I twisted the wires (stranded MTW which is also not approved) with linemans pliers applied Noalox and then tightly wire nutted them. NO problems for about 14 years.

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

 

[HCBFlash]

I haven't worked on any motors over 300HP that I can remember, but quite a lot of typical integral and fractional horsepower motors, and in a wide variety of installations and applications. The only motors I've ever encountered with fixed terminals in the connection box were IEC style, and not many of those, because it's just not a good idea.

"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

 

[ssn596]

QUOTE
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

 

[controlsdude]

Looking at all these emails I still believe wire nuts are ok for motors, but based on the code their now outlawed according to NFPA 79.

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.

 

[MagneticFlux]

Peebee,

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).

 

[raidun]

Hi everyone, there is a new product on the market which can be used for smaller motors. Looks like these wire nuts meets NFPA79 requirements, since they have UL and CE rating.

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://www.panduit.com/search/search_results.asp?N=5000001+532&Ne=1&region=USA&Nu=P_RollupKey

 

[steelerr]

Me again - I've been told to look at these 3M lug insulating kits. I thought you might be interested. Thanks again for participating in this thread.

steelerr

http://solutions.3m.com/wps/portal/...cts/?PC_7_0_21K4_nid=DJP8HB7PHMbeCSPPTQMPT8gl

 

[steelerr]

OK, here's what we've decided to use. All of these wiring connectors are UL and CSA listed.

For up to (2) AWG 10, Panduit JN314-412

http://www.panduit.com/search/produ...1&N=5000001+4294926432+3000502+&wildcard=true

For smaller wires in the motor termination box, Panduit JN218-216

http://www.panduit.com/search/produ...1&N=5000001+4294926437+3000502+&wildcard=true

For larger than AWG 10, Burndy Uni-Tap connectors

http://portal.fciconnect.com/portal...splayStyle$domProductQueryName=bit*$OP=search

Again, thanks for your interest and participation