Wirenuts in Classified Area 4

[controlnovice]

We have a NEMA4 junction box in a Class I, Div 2 area. The equipment inside is rated for Class I, Div 2. The wires coming in are connected via wirenuts.

Are wirenuts acceptable in Class I, Div 2 areas??? I'd rather see a terminal block. I can find terminals rated for Ex locations (Cenelec - maybe ATEX now?). Does the terminal block have to be rated for Class I, Div 2 in a NEMA4 j-box?

 

[rbalex]

peebee,

all of the above - as you said they are not prohibited in US domestic work.

The original question was:
Are wirenuts acceptable in Class I, Div 2 areas??? I'd rather see a terminal block. I can find terminals rated for Ex locations (Cenelec - maybe ATEX now?). Does the terminal block have to be rated for Class I, Div 2 in a NEMA4 j-box?

"Twist on" type connectors are acceptable in non-explosionproof enclosures in Division 2 per 501.4(B)(4) and they are acceptable in NEC Zone 2 per 505.20(C) Ex 3. They are NOT acceptable in IEC/CENELEC "Zones" unless they are in an Exd (flameproof) enclosure. IEC considers non-Exe connectors to be arc-making; the NEC doesn't. This is one of the few places the IEC hazardous location standards are more restrictive than tne NEC.

In Europe, it is common practice to terminate all wiring in classified locations(including lighting) on Exe terminal blocks.

 

[hacksaw]

I have to agree with rbalex.

The NEC only covers minimum requirements not necessarily what is safe for a particular environment.

Terminal boxes in Div 2 areas are a subject of contention. The assumption is that the person opening them is exercising due caution and an assumption that they are properly closed up.

 

[mc5w]

Wirenuts(R) are acceptable but the Consumer Product Safety Commission says the Scotchloks(R) are the superior device. They also say that the wire strands have to be cleaned with #220 or #240 silicon carbide abrasive paper. Cleaning the wire strands is the Old Signal Corps method of preventing open circuits and fires. #800 acceptable (my opinion) for fine stranded wire. They also say that you should be using electrical joint compound such as Burndy Penetrox(R) E for copper wire and Penetrox(R) A or A13 for aluminum wire. The latter 2 compounds also for aluminum conduit threads and galvanized steel conduit threads.

One of the other Old Signal Corps specifications was that Wirenuts(R) and Scotchloks(R) have to be taped to that vibration and handling will not unravel the connection and so that a deenergized wire connot poke into something that is energized. Someone tried to tell me that taping a wirenet(R) was a sign of a bad electrician and told him that he never got his fingers burned by a loose wirenut.

Mike Cole, mc5w@earthlink.net

 

[peebee]

mc5w -- interesting post.

Can you clarify if those statements are applicable to general-purpose installations, or if they are specific to XP installations?

I've never heard of the CPSC being referenced in context to construction requirments before, I never realized they issued codes/standards/guidelines which might be applicable.

Any thoughts on CPSC jurisdiction? What are these, nice ideas or mandatory requirements, or somewhere in between?

I'm going to go out on a limb and suggest that almost nobody uses sandpaper or joint compound on copper wires, nor do they tape the wirenuts. Any thoughts on that?

Not trying to argue with you here, just explore a bit and get a better understanding.

 

[rbalex]

I'm aware of such a CSPC position paper with regard to aluminum house wiring:

http://www.cpsc.gov/cpscpub/pubs/516.pdf

In absence of some local adoption, I doubt it is enforceable.

As a general statement: there is no NEC basis for prohibiting "twist on" type wire connectors in Class I locations, Division or Zone - period. There may be additional requirements under 501.5(A)(1)(2) or 505.16(B)(2)(a)(2), but ANY form of "...terminals, splices, or taps" would be similarly affected; "twist on" connectors have no unique restrictions.

 

[minimalibu]

There should be a certification number on the j-box. The cert. will specify the type of connections, the number of connections etc. There will be a power callculation for the box which will determine how many cables can be terminated dependent on the load.Ref to IEC 61241 IEC 60079 ANZ 2381/2380

 

[Noway2]

Sort of off topic but this discussion line reminded me of this...

I had a former co-worker who used to be an electrician in Hungary. He said that when he came to the USA, he got a job as an electrician. He said that when he first saw the use of wirenuts that he wondered what kind of idiot would use a "f*****g plastic cap" for an electrical connection.

 

[dogleg43]

Wirenuts in classified areas are acceptable per the NEC, but the customer's spec's may not permit them.

Wirenuts are no different than any other termination. They need to be installed correctly.

How many times have you found a loose wire under a terminal, or loose strands of wire from one terminal making contact with the terminal next to it.

Another option is the "push-in" style terminals that WAGO and everyone else has. I've only used them on one project and haven't got a warm and fuzzy feeling for them yet.

 

[Noway2]

One of the production lines where I work was plagued by loose connections and wire whiskers with screw type terminals. They switched to the cage clamp style like Wago, which solved the problem.

I have heard that there used to be problems with this style of connector, though I get the impression that these problems have been solved in modern varients.

 

[nmark]

In regards to the question I have used wirenuts in div 1 class 1 locations in the appropriate rated boxes.It is not a NEC violation to the best of my knowledge.I also have had to troubleshoot control wiring and power wiring with wirenuts and terminal blocks problems.A lot of wiring problems could be attributed to one cause HUMANS INSTALLING THEM regardless of wiring method.In my experience noalox/penetrox and taping of wirenuts would eliminate some problems or at least delay them in extreme enviroments.Terminal blocks our prone to the same corrosion problems and are not solved as easily as joint compound and black tape.