Terminate unused conductors to equipment ground

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Natfuelbilll

Senior Member
Any thoughts on terminating any unused conductors to equipment ground (spares in a multiconductor cable, or spares in a metal conduit) in an industrial control panel?

What is the strongest Code section that supports your reply?
 
chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Natfuelbilll said:
Any thoughts on terminating any unused conductors to equipment ground (spares in a multiconductor cable, or spares in a metal conduit) in an industrial control panel?

What is the strongest Code section that supports your reply?
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Depending on the size, color and number of conductors, you could have issues with 250.119 and 310.4.
 
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Natfuelbilll

Senior Member
1. Why then would one have to bond HVAC ductwork, or a piping system?

2. Voltage imposed by lightning or line surges on this floater?

3. A distinction of only grounding out one end of this spare conductor can be considered too.

4. Does 310.4 prohibit this grounding of < 1/0 AWG spare conductors?
 
tom baker

tom baker

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Bremerton, Washington
For small conductors I use a short length of heat shrink, and lable the wire spare, dress it in with the others. I would have a problem grounding it due to the change in the 05 NEC in 250.119
 
Rockyd

Rockyd

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Location
Nevada
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Retired after 40 years as an electrician.
I'm with Tom Baker on this one. Oil patch, we always pull a couple of spares in pipe, or allow exra conductors in a cable. Especially when the client has a tendency to "change their mind", or not be 100% certain.

Our specs for most pipeline work from the 400 manual says "Cables and wires including spares at both ends and also in pullboxes with tag numbers shown on drawings and/or conduit and cable schedules. Then again, that is just a local thing where I'm at.
 
iwire

iwire

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Massachusetts
Natfuelbilll said:
1. Why then would one have to bond HVAC ductwork, or a piping system?
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There are specific sections of code that address those systems, the likelihood they will somehow be energized from a circuit and exposed to contact from personal.

2. Voltage imposed by lightning or line surges on this floater?
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How is lightning going to strike the 'floater'?

IMO the lightning strikes they are talking abut are those hitting the overhead utility lines connected to the building wiring system.

4. Does 310.4 prohibit this grounding of < 1/0 AWG spare conductors?
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No, not in my opinion but I do think Chris brought up some posable issues.
 
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Natfuelbilll

Senior Member
mdshunk said:
I'm just wondering what's wrong with putting a wire nut on it.
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I suppose if BOTH ends are capped with a wirenut. Maybe it is a bigger problem if one end was tied to ground and the other end left bald.



What if the wire is left bald at both ends.....?




On shielded control cable the shield is grounded at one end, and taped back at the other end. This taping is basically the same as a wire nut....
 
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