Electric cable, 32amp.

[manortim]

Need to run a cable in duct under ground.

It will have no greater than a 9kw demand. only single phase

Approx length....30m.

What size cable do i need and where would be cheapest to get, dont have electracenter account only pts.

Also, can i run a phone cable and cat4? (internet cable) in same duct

Thanks.

 

[plugwash]

Before the cable size can be calculated answers to the following questions are needed

1: where is it fed from? if it's the origin of the installation then that makes things easy. If it's not the origin of the installation then volt drop in the submains feeding it will have to be considered (which may be difficult if accurate records have not been kept).
2: will it be feeding any lighting? starting from the 17th edition lighting circuits have more stringent volt drop requirements than other circuits.
3: what is the earth fault loop impedance at the board the circuit is fed from and what will the protective device be?

If you will be using an electrician I would reccomend asking them as they will be the ones who will have to sign it off.

As for running phone and network cable in the same duct I belive it's ok because of the earthed metal surrounding the mains conductors in the SWA but i'm not positive on that.

 

[ban-all-sheds]

Need to run a cable in duct under ground.

It will have no greater than a 9kw demand. only single phase

Approx length....30m.

What size cable do i need

• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html <- Specify 2-core cable and PVC, even if that is not what you are using or it will make invalid assumptions.
  

You should also read this: //www.diynot.com/wiki/electrics:part-p

Also, can i run a phone cable and cat4? (internet cable) in same duct

No, not unless the phone and network cables are insulated for 230V. Use a separate duct.

And don't use Cat4 for networking, use Cat5e or Cat6/6a.

 

[bhm1712]

Yes Cat 4 is useless, only rated upto 16mb/s if i remember rightly. Its several generations of comms cable out of date! do Cat 6/6a and you will be fine upto 10Gigabit Ethernet. So pretty much future proof for the UK broadband supply for the next 10-15 years. Unless miracles occur. Great for LAN comms as well. Get the associated hardware and you can transfer huge files in seconds.

Dont put the comms stuff in the same conduit as the electricity supply, as B-A-S has already said, unless it is insulated for 230v.

 

[bernardgreen]

Do not use CAT cable for the cable carrying the phone signal to the router / ADSL modem as the ADSL signal is designed for use over telephone cable and not CAT data cables.

 

[PrenticeBoyofDerry]

Need to run a cable in duct under ground.

Do you know the required depth for this

It will have no greater than a 9kw demand. only single phase

That would be nearer 40A than 32A, who have you calculated this demand/load

Approx length....30m.

If lights are being supplied for this could effect the size of cable due to voltage drop

What size cable do i need and where would be cheapest to get, dont have electracenter account only pts.

For 9kW @ 230V with power and lights likely to be 10mm, without any other derating factors. As far as cheapest you would have to shop around and inquire about prices, i am not local to your area so could not offer any other advice on cost.

Also, can i run a phone cable and cat4? (internet cable) in same duct

They would need to be rated at the highest voltage cable within the duct or circuit separation within compartments would be required, to prevent any induced voltage between the two.

 

[SimonH2]

Do not use CAT cable for the cable carrying the phone signal to the router / ADSL modem as the ADSL signal is designed for use over telephone cable and not CAT data cables.

Actually good data cable (eg Cat5e) is good for ADSL signals. Yes, ADSL is designed to work over phone cable, but that's a case of "making it work over poor cable" rather than "works better than over good cable".

You can, at great cost, get SWA data cable (I've worked with it on a couple of jobs - though fibre optic would have been better if the customer wasn't a tight a**e) - and if you earthed the wire armor then you could probably justify running it alongside an SWA power cable.
Probably cheaper to just run a separate duct along side (at least 6" away from) the power cable/duct. A separate duct would also offer future proofing as you could pull in new cables if your requirements change.

 

[manortim]

ok,

i am going to run it in 16mm 2 core cable. into the duct, does it need to be armoured if its in a duct?

also, will the sparkie need a earth point?


the cable goes from the mains isolation point in 1 workshop, under ground to a new work shop.

i have to run the cable and the sparkie should sort the rest.

lucky him as he is in OZ until 21st.

will he need so sort of earth point as the new workshop is a steel framed dutch barn.

or....will it need 3 core cable with 1 of the cables as a earth? or do i run a single earth cable in the duct?

thanks.

 

[PrenticeBoyofDerry]

What earthing arrangement do you have at the consumer unit.
//www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements
If the metal frame is exposed it would need bonding.
//www.diynot.com/wiki/electrics:main_equipotential_bonding

will it need 3 core cable with 1 of the cables as a earth? or do i run a single earth cable in the duct?

Use SWA 3 core, then one core is used as live, one as neutral, one as CPC earth and the armour is terminated using glands and used as additional earth protection.

 

[ban-all-sheds]

lucky him as he is in OZ until 21st.

For the sake of 3 days wait until he is back, and then you can ask him all these questions.

He should be the one to make those sorts of decisions anyway, as he is the one who you'll be expecting to sign certificates saying he designed it.

 

[securespark]

Wait!

You're running this cable not from the origin but from a workshop fed from the origin.

You must ensure that the existing supply cable to the workshop you intend to run off is up to the job of feeding the additional 9 kW, plus the existing loads. Also, that the Zs and volt drop calculate OK for the existing workshop supply.

It's absolutely no use to man or beast if the supply cable to the workshop you intend to feed off is inadequate to begin with.