NFPA79 and Solder Splices

[Jieve]

Hi all,


something I've been wondering about for a while now. Is there anything in the NFPA79 restricting soldering cable ends together to extend cable lengths? Here are a few tidbits I've found:


13.1.2.1: Conductors and cables shall be run from terminal to terminal without splices or joints. Plugs/receptacles with protection against accidental disconnection are not considered splices/joints for this requirement. Exception 1: Splices are permitted to leads attached to electrical equipment (solenoids, motors, etc). Such splices need to be insulated with oil resistant electrical tape. Exception 2: where it is impractical to provide terminals in a junction box.



13.1.1.5: Soldered connections shall only be permitted where terminals are provided that are identified for soldering.


13.1.2.2: Mating molded nylon connectors using crimped terminations shall not be considered a splice or joint when used in an enclosure or conduit.



It sounds to me like soldering cable for use with field devices would fall under exception 1 under 13.1.2.1. But what is the exact definition of "leads attached to electrical equipment"? Would this include sensors or instrumentation with fixed, permanently attached cable lengths dictated by the manufacturer? Would soldering extension cables in such applications for use in conduit be allowable? Or even run along a machine, assuming properly insulated?



Also, what about soldering cables/wires inside of an enclosure (within duct) to extend their length when not long enough?



Context: We have 4-20mA pressure sensors that need to be installed at compressor inlet and outlet that only come with fixed cable lengths, and the controls enclosure is located some distance away.

 

[pturmel]

You quoted 13.1.1.5. Seems a pretty clear "No" for soldered splices.


Sounds like you need a junction box with a terminal strip at the compressor. Aside from the standard, I'd be pretty upset with a vendor that deployed a system with splices in sensor leads.

 

[Jieve]

13.1.1.5 is under "Connections" which gives the impression that they're talking about connections to terminal blocks, controls components, etc. as opposed to splicing wires together.



To me, I would consider soldering wire ends together "splicing", which would be covered under 13.1.2, but it seems a little unclear, hence why I pose the question.

 

[Snyd1]

I would have no problem doing it and shrink wrapping for a 4-20mA sensor, but cannot comment on the code. An alternative field wire some M12 connectors for easy replacement.

 

[bill4807]

I don't know about 4-20mA sensors, i would be inclined to solder those.
But for digital sensor sensors with fixed cable lengths, i would use field wirable M12 or M8 connectors then buy a molded cable for the extension.
I always run into this issue with small gripper reed switches. Some i can buy with m8s but some only come with flying leads. Even though im not a fan of the field wirables, i like the molded cables whenever i can.

 

[James Mcquade]

you have already found your answer, which is no.

13.1.1.5: Soldered connections shall only be permitted where terminals are provided that are identified for soldering. this is referring to terminals specifically designed for soldering, for example, amphenol connectors. the wire connections are typically designed to be soldered.

you might look at pressure released butt splices.

regards,
james

 

[Jieve]

Thanks everyone for your responses.


Actually re-reading 13.1 in context I am starting to interpret 13.1.1.5 as meaning no soldering in general for both wire splices or components (other than connectors designed for the purpose).