Oversleeving Flexible cord cores?

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AdrianWint

Senior Member
Location
Midlands, UK
Gents,

I'm having a discussion with one of my fellow Engineers.....

The scenario is that we have a UK built product destined for a US (educational) Customer. The device is intended to run HOT-HOT from a 208-240V supply (it requires around 10A and isn't frequency dependant). It is proposed to fit a 3 conductor cord (HOT, HOT, Ground. No Neutral required).

Our buying department has not been able to source a suitable cord, so the suggestion is to use a grey/green/black cord & to oversleeve the grey conductor in red at each end to make the cord Red/Black/Green.

My question is : Will this fly?

(I seem to remember that our UK regs require a flexible cord to be identified through-out its length so this precludes the practice of oversleeving)

Your comments greatly appreciated.
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
Since you are only drawing around 10 amps, I suspect the cheapest and "cleanest" solution is a 4 conductor cable.
 

Smart $

Esteemed Member
Location
Ohio
Yes where the NEC applies.

200.7 Use of Insulation of a White or Gray Color or
with Three Continuous White or Gray Stripes.

...


(C) Circuits of 50 Volts or More. The use of insulation
that is white or gray or that has three continuous white or
gray 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 or gray 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 or gray
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.

Informational Note: The color gray may have been used in
the past as an ungrounded conductor. Care should be taken
when working on existing systems.
 

norcal

Senior Member
Why not use a cord with brown/blue/yellow w/a green stripe? Blue & brown are both considered a hot/live conductors, plus it would be a off the shelf item on the other side of the pond, or would the use of blue be a problem because being a neutral in the UK?
 

AdrianWint

Senior Member
Location
Midlands, UK
Why not use a cord with brown/blue/yellow w/a green stripe? Blue & brown are both considered a hot/live conductors, plus it would be a off the shelf item on the other side of the pond, or would the use of blue be a problem because being a neutral in the UK?

Such a cord would indeed be off-the-shelf here in the UK & would be our 'standard' flex fitted here.

The device in question is happy being powered L-N @ 230V or L-L @ 208-240V - that was a design brief, so it wouldn't matter that about the blue being neutral here in the UK as long as its acceptable being a HOT in the US.

I had assumed that supplying the flex with UK colours would be negative point for sales into the US..... are you suggesting that a piece of kit turning up with Brown/Blue/Green&Yellow cores wouldn't confuse a US Customer? Would they not expect to see familiar colours and not some 'foreign' colour scheme?

What about our UK flexible cords being metric & not imperial? We'd normally fit a 1.5mm2 flexible cord to this device .. this would be somewhere between a 14 & 16 gauge. How would this be received?

Ideally, the solution would make the product acceptable in both the US & Canada. I'm aware that the L1 & L2 colours (black & red) are transposed between US & Canada and I've been told that they have an issue with a brown/blue/green&yellow cord hence the suggestion to fit a red/black/green cord set.

We did consider supplying a 4 core cable (& insulating the neutral at the product end)..... but would this not suggest to the User that a 4 pin receptacle was required, thus limiting the number of suitable receptacles types, when if fact the neutral isn't actually required for operation?

Smart$ - Thank-you for the NEC quote. It would seen that oversleeving is fine.

Thank-you all for your time & comments so far. Your help is much appreciated.
 

Smart $

Esteemed Member
Location
Ohio
I think Brown/Blue/Green-Yellow cord is fine. The G-Y insulation is compliant with the NEC:

250.119 Identification of Equipment Grounding Conductors.
Unless required elsewhere in this Code, equipment
grounding conductors shall be permitted to be bare,
covered, or insulated. Individually covered or insulated
equipment grounding conductors shall have a continuous
outer finish that is either green or green with one or more
yellow stripes except as permitted in this section. Conductors
with insulation or individual covering that is green,
green with one or more yellow stripes, or otherwise identified
as permitted by this section shall not be used for ungrounded
or grounded circuit conductors.

The color of ungrounded conductors is only required in specific instances (though they can never be the color of a grounded or grounding conductor)... and in those scenarios it would be upon the installer to adequately mark as such. As a manufacturer, you cannot anticipate when those scenarios arise.

Wouldn't hurt to include a wiring diagram in the documentation. :D
 

Smart $

Esteemed Member
Location
Ohio
...
What about our UK flexible cords being metric & not imperial? We'd normally fit a 1.5mm2 flexible cord to this device .. this would be somewhere between a 14 & 16 gauge. How would this be received?
...
You haven't provided enough detail to make the call...

What is the maximum current draw under any nominal condition?

Can that maximum draw last for more than 3 hours continuously?

Is this product listed by any US-recognized testing laboratory?

Is the cord being furnished as part of the product, or an accessory thereof?

Are you looking at supplying with a plug already installed?
 

fmtjfw

Senior Member
BUT we normally consider light blue to be a neutral in power cords

BUT we normally consider light blue to be a neutral in power cords

NEC 2014 400.22(C) [Flexible Cords and Cables -- Grounded-Conductor Identification -- Colored Insulation] states:
A white or gray insulation on one conductor and readily distinguishable color or colors on the other conductor or conductors for cord having no braid on individual conductors.
Foe jacked cords furnished with appliances, one conductor having its insulation colored light blue, with the other conductors having an insulation of a readily distinguishable color other than white or gray.

Exception: Cords that have insulation on the individual conductors integral with the jacket.

The insulation shall be permitted to be covered with an outer finish to provide the desired color.

NOTE: The Code permits light blue to be considered a neutral and those familiar with internationally-sourced equipment or power cords potentially for use in world markets expect light blue to be the neutral conductor.
 
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