Functional Spare

[TwistLock]

As you can only use / re-identify the white insulation/neutral in an NM cable as the supply to a switch loop per 200.7(C)(2), so then I assume you can not (example) use a 10/2 NM cable, with black / white conductors, for 240v branch circuit by identifying the white as an ungrounded conductor. So I thought the workaround was using a 10/3 NM cable and capping off the white wire both ends & just using the black/red (no EVSE outlet, say perhaps HVAC). Except I read(?)that 300.3(B) prohibits this too.
But then we get into 404.4(C) and the neutral is capped, not terminated, at the switch box and intended for future use. So why can’t an unused neutral in my 10/3NM 240v circuit be categorized as a functional spare?

 

[ptonsparky]

When did remarking a white in a two wire NM cable for 240 volt application become prohibited? Always and forever did it and prior to that we didn’t need to mark it.

A white wire is not necessarily a neutral, especially when it’s not connected to anything. It’s just a spare.

Define functional spare.

 

[infinity]

You can re-identify a white conductor in any 2-wire cable as an ungrounded conductor for a 240 volt load. Spare cable conductors can be capped and left for future use.

 

[TwistLock]

When did remarking a white in a two wire NM cable for 240 volt application become prohibited? Always and forever did it and prior to that we didn’t need to mark it.

A white wire is not necessarily a neutral, especially when it’s not connected to anything. It’s just a spare.

Define functional spare.

Same here, but inspector cited 300.3(B) in a sub change out where an existing 10/3NM where neutral was left capped going to HVAC (I left it that way thinking there may be a good reason, like a nail etc., instead of connecting to neutral bar) and an existing 10/2 re-identified for another circuit. I argued both, but he also (confidently) brought up 200.7 in that case. So I assumed I've been wrong, but still couldn't understand his beef with a 10/3 then.

 

[TwistLock]

You can re-identify a white conductor in any 2-wire cable as an ungrounded conductor for a 240 volt load. Spare cable conductors can be capped and left for future use.

I've been hosed. Contacting supervisor.

 

[roger]

200.7 (C)

(C) Circuits of 50 Volts or More. The use of insulation
that is white or gray or that has three continuous white
stripes for other than a grounded conductor for circuits of
50 volts or more shall be permitted only as in (1) and (2).
(1) If part of a cable assembly that has the insulation permanently
reidentified to indicate its use as an ungrounded
conductor by marking tape, painting, or other
effective means at its termination and at each location
where the conductor is visible and accessible. Identification
shall encircle the insulation and shall be a color
other than white, gray, or green. If used for single-pole,
3-way or 4-way switch loops, the reidentified conductor
with white or gray insulation or three continuous
white stripes shall be used only for the supply to the
switch, but not as a return conductor from the switch to
the outlet.
(2) A flexible cord, having one conductor identified by a
white or gray outer finish or three continuous white
stripes or by any other means permitted by 400.22, that
is used for connecting an appliance or equipment permitted
by 400.7. This shall apply to flexible cords connected
to outlets whether or not the outlet is supplied
by a circuit that has a grounded conductor.

 

[infinity]

I've been hosed. Contacting supervisor.

What logical reason would prohibit a spare conductor in a cable?

 

[TwistLock]

200.7 (C)

Exactly, this is what I just looked up. He's isolating the requirement for Switch Loops to mean everything else.

Most inspectors just say "Hi & Bye" or "Did you do X, Y & Z?" to which I reply "Yup" and they're gone. But this guy was very sure of himself.

 

[TwistLock]

What logical reason would prohibit a spare conductor in a cable?

He said a true spare must be terminated on both ends. I thought I was learning something nuanced. I was just arguing with a lunatic.

 

[roger]

He said a true spare must be terminated on both ends. I thought I was learning something nuanced. I was just arguing with a lunatic.

He's confusing these cables with Chapter 8 abandoned cables

 

[roger]

Exactly, this is what I just looked up. He's isolating the requirement for Switch Loops to mean everything else.

He needs some reading education

 

[infinity]

He said a true spare must be terminated on both ends. I thought I was learning something nuanced. I was just arguing with a lunatic.

If it were terminated it wouldn't be a spare. I feel for guys that have to deal with such incompetent inspectors.

 

[kwired]

If it were terminated it wouldn't be a spare. I feel for guys that have to deal with such incompetent inspectors.

Only way it is a spare is if it terminates in some terminal block that has an open port for future extending to something else. Something maybe more common with raceway/wireway methods than with cable wiring methods.

Landing a conductor on a breaker or on neutral bus at the panelboard designates it's use to a certain extent even if the other end of the conductor happens to just be capped/taped.