Thermostats sharing lightswitch conduit?

[thompo]

Hello

Just thinking about where i am going to be installing thermostats throughout the house (7 zones, 7 stats)

They are 12v stats (Heatmiser PRT-N) powered by the wiring center and i plan wire them with Cat5 as per instructions.

Is there any issue using the conduit already insitu for light switches or sockets to get my cat5 down the wall?

eg

Untitled

• thompo
• 14 Aug 2013
• 1

Cheers Neil

 

[PrenticeBoyofDerry]

The insulation has to match the rating of the highest voltage conductor.

 

[thompo]

Good stuff.

Seeing as the lights are 240v and these cables are running in the same conduit as the cat5 will i have to check the spec for the Cat5 i have to see if its insulation is rated to greater than 240v? Or is it the conduit that must have a suitable rating?

Thanks

 

[JohnW2]

Seeing as the lights are 240v and these cables are running in the same conduit as the cat5 will i have to check the spec for the Cat5 i have to see if its insulation is rated to greater than 240v? Or is it the conduit that must have a suitable rating?

Yes and No respectively. I have no doubt that the insulation of cat5 cable can happily cope with 230V but I fear that you'll find that the specifications indicate a much lower voltage 'rating' than that. If that's the case, you would not theoretically be allowed to include it in the same conduit as cables carrying 230V.

Kind Regards, John

 

[ban-all-sheds]

Didn't we establish recently that at least one (was it Draka?) maker does produce Cat 5 or Cat 6 cable where they officially rate it to 230V (presumably to allow it to share containments)?

It may not be what the OP has, but he could get suitable Cat 5 if he needs to.

 

[JohnW2]

Didn't we establish recently that at least one (was it Draka?) maker does produce Cat 5 or Cat 6 cable where they officially rate it to 230V (presumably to allow it to share containments)? It may not be what the OP has, but he could get suitable Cat 5 if he needs to.

I remember the discussion, but confess that I can't remember the bottom line - so you may be right. As you say, if such a cable exists, the OP could get some if he wishes to comply with the regs in this respect.

Kind Regards, John

 

[Lectrician]

The Heatmiser stuff also specs FTP (foil) due to the delicate data of the data pair if you use the "whole house" central control unit (which you don't need to).

The other pairs are used simply for 12v +/- and a switching pair. Only one single pair carries any data. This is useful to know, because it means you can back-to-back these stats on the wall, using one cable to feed both.

Four pairs, one pair 12v supply to both stats, one pair data for both stats, two pairs for a switching contact to each stat.

 

[ban-all-sheds]

Didn't we establish recently that at least one (was it Draka?) maker does produce Cat 5 or Cat 6 cable where they officially rate it to 230V (presumably to allow it to share containments)? It may not be what the OP has, but he could get suitable Cat 5 if he needs to.

I remember the discussion, but confess that I can't remember the bottom line - so you may be right. As you say, if such a cable exists, the OP could get some if he wishes to comply with the regs in this respect.

Yo - this is what I was rememberifying:

from http://www.drakauk.com/products/special_cables/special8.php

DC LOOP RESISTANCE: ≤ 190 Ω/km

RESISTANCE UNBALANCE: ≤ 2%

INSULATION RESISTANCE (500V): ≥ 2000 MΩ/km

CAPACITANCE AT 800Hz: nom. 48nF/km

CAPACITANCE UNBALANCE (PAIR TO GROUND): ≤ 1500 pF/km

CHARACTERISTIC IMPEDANCE (1-100 MHz): (100 ± 15)ΩΩ

NOMINAL VELOCITY OF PROPAGATION: Approx 67%

PROPAGATION DELAY: Nominal ≤ 535 ns/100m

DELAY SKEW: Nominal ≤ 20 ns/100m

TEST VOLTAGE (DC, 1 min) CORE/CORE: 1000V

So confirmation from Draka is needed.

 

[JohnW2]

Yo - this is what I was rememberifying:

from http://www.drakauk.com/products/special_cables/special8.php
... TEST VOLTAGE (DC, 1 min) CORE/CORE: 1000V

So confirmation from Draka is needed.

Thanks. Was there an AC test voltage mentioned? If not, pedantic though it might be, can one actually say that this cable is 'rated' for 230V AC? Also, was there anything otherthan a core/core voltage test mentioned - since, again pedantic, that is not quite what matters when it comes to cables in proximity.

Kind Regards, John

 

[ban-all-sheds]

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