Where to buy electrical cable 6491X

[deema]

I’m looking for somewhere between 200 and 500m of 4mm2 in the usual 5 colours to wire up the workshop. Where’s the best place to buy it from these days and what sort of price should I be expecting? (I’m going to wire the earth in 4mm2 too)

 

[HOJ]

I can see google getting a hit searching for what 6491X is...

No help otherwise.

However, why 5 colours, can you not just use 3?

 

[Spectric]

What is it supplying, also how did you arrive at requiring 4mm ? Then is this armoured or ?

However, why 5 colours, can you not just use 3

Not if using it for three phase and neutral with a CPC . 4mm at 500 metres is a 1Km loop ! Must be looking at around a 10mV drop per amp per metre .

 

[Spectric]

Ok, you slipped in the 6491 in the title ! so these are singles for wiring within the workshop. I would use 6491 B, the low halogen version for something more industrial that you are doing and readily available. Try TLC direct or Ewardes and should not be more than about £55 per 100 metres.

 

[Sideways]

Eddies & Denmans in your part of the world ...

 

[deema]

When wiring up, I anticipate that any socket could be single or 3 phase 32A, and build in redundancy. I’ve placed trunking around the workshop at ceiling level, so to get to a machine the wiring has to run around the shop. I have 12 machines that need wiring up, and don’t have their position determined yet. I’m hopeless at layout without actually moving the machines about. Luckily @Sideways has been press ganged to give me a hand / lead the layout. He’s brilliant at creating a layout / maximising space utilisation.

500m might be two much, however it might be more economic than buying a number of rolls of 100m. My last workshop had in the end 1km of cable, mostly due to machines moving and taking the decision in most cases to put new drops in rather than jointing cables.

 

[Spectric]

When wiring up, I anticipate that any socket could be single or 3 phase 32A

Please explain. Three phase sockets, isolators etc run from the main board as individual radials from there own protective three phase device the same as 16 amp socket, isolators etc that run from there own single phase protective device and single phase sockets that accept fused plugs can run as a radial looped in and out so a string on a given protective device that would be 32 amps if run in 4mm. Here you need to do some thinking as you can run these in 2.5mm cable and use a 20 amp protective device bearing in mind that you will probably have several radials to different areas.

and taking the decision in most cases to put new drops in rather than jointing cables

Done correctly there are no issues, but good practice does state no joints within the trunking so you would need to use an enclosure so the cables exit and re enter the trunking with decent connectors.

 

[deema]

@Spectric I really appreciate your insights and questions. Hopefully I can explain my logic. Any radial drop for a machine could be over the passage of time a say a 16/ 32A Single phase or 3 phase, or anything in-between as things change. My workshop over the last seven years changed both in where things were positioned and as I updated / changed machines. So, in anticipation that this will continue…..as I am a bit of a magpie, what ever a drop is designated to be to begin with the initial shop layout I will just run it in 4mm, that way I can change it by either adding extra phases or isolating phases phases to adapt it to what it needs to be. (I appreciate that also involves changing the isolated output socket as well as the distribution board)

The ring main for 13A sockets will probably be run in 2.5mm (probably twin and earth as it’s cheaper than singles) (I need to do the loading calcs as I’ve a feeling the length / load may need 4mm2, what do you think?) it’s around 70m (50m in the trunking) run including the drops.

 

[Spectric]

probably twin and earth as it’s cheaper than singles

But remember the CPC in a 2.5 mm T&E is only 1.5mm and if running trunking then sticking T&E in there will look like a short cut, 2.5 singles are not that expensive and again will offer more flexability in the future. Also something to note is that you should keep all your 13 amp sockets fed from the same phase within the workshop.

The ring main for 13A sockets will probably be run in 2.5mm

Ring mains are historic, search the forums as it has been discussed. Use radials for your 13 amp sockets and that means that once you reach the last socket there is no cable run back to the board. If using 4mm cable and a 32 amp circuit getting two 4mm cables into the face plate can be tight, in these cases using small enclosures and Wago connectors is the solution. Do the calcs on loading and run your 13 amp sockets from several radials, that way you will not have a 70 metre run and maybe use one for say half the workshop and another for the other half so then you might find you can use 2.5mm singles and a 20 amp protective device.

 

[deema]

@Spectric I know rings are ‘old fashioned’, but they do provide IMO redundancy for a single CPC fault. I kind of favour running a radial rated cable but making it into a ring. Sounds daft I know, but it means should the CPC connection fail anywhere I have a back up circuit.