Are DC + and - considered as "Active"s in 3000

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JamieP
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Are DC + and - considered as "Active"s in 3000

Post by JamieP »

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Would this definition also include DC + and - conductors? Because to me it seems so
AlecK
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Re: Are DC + and - considered as "Active"s in 3000

Post by AlecK »

Yes (technically); for an un-earthed d.c. system

Though note that in 2.3.2.1.1; which sets requirements for a.c & d.s systems; the words 'active" & "neutral" are used only for a.c.

I suspect this is just the background bias towards LV a.c. that exists throughout "3000"
I'll have to check what the IEC terminology is
JamieP
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Re: Are DC + and - considered as "Active"s in 3000

Post by JamieP »

First of all, welcome back Alec hah

The reason for my question is trying to answer the question of DC colour usage and I totally understand that 3000 is very bias in this regard

This springs from seeing green ,very common in control cables multicores and even green/yellow used in ELV DC systems

The restriction on green, yellow and green/yellow seems to only apply to active and neutral conductors, hence the question arising

I do also understand you can eliminate any colour scheme but using a means other than color as identification and these votes are always labelled but often don't mention if + or -, A, N or E, does it matter?
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Re: Are DC + and - considered as "Active"s in 3000

Post by pluto »

In the IEC the colour code for installation cables have a differerent colour alocated for AC and DC cables. There is no common colour code for AC and DC cables, live or otherwise.
AlecK
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Re: Are DC + and - considered as "Active"s in 3000

Post by AlecK »

The colour codes specified in "3000" [3.8.1 / Table 3.4] apply only to "installation wiring".
That includes the "absolute" ban [3.8.1 & 1.7.2] on green, yellow, or green-yellow for active or neutral.

In most cases signal cables are not "installation wiring" .
Where it is 'installation wiring", and colour is used as OD, then it would be non-compliant IMO.
However there is a bit of a grey area around d.c.; as you've identified.

Next (after 2018) edition of "3000" is hoped to be more comprehensive about a number of areas, where currently the 'rules" are almost completely based on the concept of supply ex grid at LV 50 Hz, and what little d.c & ELV is there us almost an afterthought
JamieP
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Re: Are DC + and - considered as "Active"s in 3000

Post by JamieP »

"In most cases signal cables are not "installation wiring""

Could you elaborate a bit more on this? I am new to the industrial game but most of the control cabling seems to be supplied via a 24V power supply with a 230V feed in

Wouldn't this still be part of the installation? And installation wiring

Is there other systems your seem to be referring to or am I missing something?
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Re: Are DC + and - considered as "Active"s in 3000

Post by AlecK »

Refer definitions 1.4.101 vs 1.4.102; also clause 4.3 for demarcations between.
These make it very clear for discrete items of equipment; but rather less clear for what might be called 'distributed equipment'.

Example 1: split system heat pump.
The supply to it, through the isolating switch req'd by 4.1 and up to terminals of 1st unit, is "installation wiring".
But the wiring from 1st unit to 2nd unit is "equipment wiring".
Note that this is commonly a 3&E TPS, with both power & signal in 3 of the cores and the 4th used only for earthing.

Example 2: industrial refrigeration equipment.
Compressor, evaporator fans, solenoids(s), sensors, etc all generally supplied as discrete wiring run from a 'control panel' that is often attached to or even part of a 'switchboard'.
A good case can be made that most if not all of this wiring is "equipment wiring".
Certainly the fact that there may be overcurrent devices for some or all of it doesn't automatically make it "installation wiring" .
Eg there could be a set of fuses for the system as a whole, the conductors departing from them being a "final subcircuit".
But in many cases it can also be viewed as a submain to another 'switchboard that contains protective devices for at least some of the various sub-systems.
Depending on the exact configuration, both views may be valid - and the rules that apply depend on which view is taken.


Installing LV equipment wiring is PEW, same as for installing LV installation wiring; but colour codes as per 3.8.1 do not necessarily apply.

When the distributed equipment has ELV sensors, actuators, etc it can be even more confusing; and generally won't be PEW even when it's "installation wiring".
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