Terminating SWA with Wylex REC Supply Isolators

[johnboy6083]

As has been mentioned, if the CU is more than 3m away, it's almost certain that the DNO will require additional fusing.
i would go with individual fuses per CU, and mount the whole lot on steel trunking. It's cheap, easy to use and won't take long.
Make sure the locknuts are tight. I would fly lead from the trunking to each individual switch fuse.
will the armour on the 16mm 2 core be upto the spec for the bonding if its TNC-S? suspect not, but I'm not aware of all the facts as you are.
Don't forget that for main bonding of PME supplies, it's the conductivity that is of prime concern, unlike the adiabatic, in which limiting temperature is the concern.

 

[Michaelwgroves]

As has been mentioned, if the CU is more than 3m away, it's almost certain that the DNO will require additional fusing.
i would go with individual fuses per CU, and mount the whole lot on steel trunking. It's cheap, easy to use and won't take long.
Make sure the locknuts are tight. I would fly lead from the trunking to each individual switch fuse.
will the armour on the 16mm 2 core be upto the spec for the bonding if its TNC-S? suspect not, but I'm not aware of all the facts as you are.
Don't forget that for main bonding of PME supplies, it's the conductivity that is of prime concern, unlike the adiabatic, in which limiting temperature is the concern.

Well spotted, yes all the CU's are more than 3M away. I was just driving back and thought I should mention this, but you beat me to it. This is one reason for using the Wylex Rec Isolators. I assume they are okay for the job?

Also worth mentioning is I also chose these for size as we don't have a lot of room in the intake cupbord.

 

[HandySparks]

Well spotted, yes all the CU's are more than 3M away. I was just driving back and thought I should mention this, but you beat me to it. This is one reason for using the Wylex Rec Isolators. I assume they are okay for the job?

Also worth mentioning is I also chose these for size as we don't have a lot of room in the intake cupbord.

The Wylex REC isolators aren't fused; so not OK.

 

[Engineer54]

If you have 12 number of flat's to supply, you maybe better off thinking about a Ryefield panel at the intake cupboard Where all the fuses are located in the one panel.

What do you have there, a 3 phase DNO supply??

 

[londonlec]

All this job requires is an electrician.

 

[Octopus]

Back to the drawing board me thinks

 

[Rockingit]

Unless I've completely misunderstood all this, this sounds like a classic case of over engineering through misunderstanding. What's wrong here with Intake > KMF > 16mm TE plus additional 10mm cpc if the adiabatic is over 6mm? Easy to run, easy to terminate and much cheaper plus adding a fuse into the system.

 

[High Tower]

I second a rye field ! Or the use of 110m's there isn't really any other way. And if you have the budget to build 12 flats then you should have the budget to provide the right sub mains

 

[High Tower]

Unless I've completely misunderstood all this, this sounds like a classic case of over engineering through misunderstanding. What's wrong here with Intake > KMF > 16mm TE plus additional 10mm cpc if the adiabatic is over 6mm? Easy to run, easy to terminate and much cheaper plus adding a fuse into the system.

If they are flats then the chances are the subs would need RCD protection if ran in T&e

 

[Knobhead]

What is you’re objection to trunking? If there are 12 cables to make off I can’t think of a better option. 12 X adaptable boxes are going to look a mess.
As for the CPC E54’s table shows that you are right to use the armouring.

 

[D Skelton]

Looking to keep costs down.

Typical landlord! Smiling all the way to the bank when the rent starts hitting the bank account (I'm guessing with bedsits this will be at taxpayers expense [happy to eat humble pie if I'm wrong]) and yet not even prepared to invest a little to get a job done properly first time!

You need a 12 way ryefield, your subs run in 16mm SWA and all terminated in some metal clad DBs. IMHO, this is the only way to do the job properly.

 

[High Tower]

The only issue I have with a Ryefield is that it provides no local isolation, I have to admit my preference would be either a busbar chamber or Ryefield with 100amp 1361's a length of 8" galv trunking and a 110m or switch per flat to give local isolation .

 

[Engineer54]

The only issue I have with a Ryefield is that it provides no local isolation, I have to admit my preference would be either a busbar chamber or Ryefield with 100amp 1361's a length of 8" galv trunking and a 110m or switch per flat to give local isolation .

I would expect there to be a means of local isolation before the Ryefield panel!! You could even use a suitably sized/rated 3 phase (if this is a 3 phase installation) Fuse DB, with a main isolator. Any thing is better than the proposals put forward so far, for separate this and that's!! lol!!

 

[High Tower]

I would expect there to be a means of local isolation before the Ryefield panel!! You could even use a suitably sized/rated 3 phase (if this is a 3 phase installation) Fuse DB, with a main isolator. Any thing is better than the proposals put forward so far, for separate this and that's!! lol!!

Only problem with that is that it means the isolator would isolate all 12 flats which isn't exactly ideal

 

[High Tower]

The other option is a length of trunking to terminate SWA's into with a Hager invictus TPN DB with a 250a rating, 6x3ph way and fit it with 12x 63a single pole type c MCB's one for each flat.

http://www.hager.co.uk/products/ene...invicta-3-250a-incoming-63a-outgoing/7747.htm

 

[Michaelwgroves]

Currently single 3P coming in but waiting for UK Power to upgrade, not aware what they are gonna put in.
High power requirements for each bedsit, 10kW Shower, 9kW Hob/Oven, 5kW heating, 3kW water heater etc. etc. 60A will be tight. So safer to go with 16mm SWA to get full 100A.

I want to be able to isolate everything in the intake cupboard, can I get Hager with 12 No. 100A MCB's ?

Do I assume Ryefield is now not an option?

 

[Michaelwgroves]

Typical landlord! Smiling all the way to the bank when the rent starts hitting the bank account (I'm guessing with bedsits this will be at taxpayers expense [happy to eat humble pie if I'm wrong]) and yet not even prepared to invest a little to get a job done properly first time!

You need a 12 way ryefield, your subs run in 16mm SWA and all terminated in some metal clad DBs. IMHO, this is the only way to do the job properly.

The reason for my post is to make sure the job is done properly. From all the idea's it's obviously not any easy soloution. Thanks for all the idea's guys, keep em coming.

Sort of right with the Tax payers money, but not your usual DSS tenant, I'm working with a charity to help less fortunate people who are down on thier luck get back on track. But no offence taken from your comment, 100% correct for another property!

 

[Michaelwgroves]

What is you’re objection to trunking? If there are 12 cables to make off I can’t think of a better option. 12 X adaptable boxes are going to look a mess.
As for the CPC E54’s table shows that you are right to use the armouring.

Adaptable boxes looked a good idea at the outset, but now this has progressed I would now use trunking for the reason you say. Albeit, it looks like I will need a bigger soloution than orgionally planned, so might be able to terminate directly on new soloution.

 

[Michaelwgroves]

The Wylex REC isolators aren't fused; so not OK.

I thought 100A fused, are you sure. I thought this was what they were designed to do, or does the sub main cause the issue?

 

[High Tower]

Currently single 3P coming in but waiting for UK Power to upgrade, not aware what they are gonna put in.
High power requirements for each bedsit, 10kW Shower, 9kW Hob/Oven, 5kW heating, 3kW water heater etc. etc. 60A will be tight. So safer to go with 16mm SWA to get full 100A.

I want to be able to isolate everything in the intake cupboard, can I get Hager with 12 No. 100A MCB's ?

Do I assume Ryefield is now not an option?

You do not want your calculations running to 100a per unit, drop your shower down to 8kw job and oven to 7kw etc etc. you need to be distributing 60a per unit with 200a per phase 3ph incomer.

if you exceed this the DNO will want you to sell your soul for the cost of the upgrade for your mains. People like tony and E54 will tell you of the frightening costs of big supplies.

It's not that a Ryefield is not ideal for the job it's the fact that you will need 12 sets of tails with 12 main switches all crammed into the trunking with 12 16mm SWA's. with a big DB like this then you still have the SWA glanded onto the trunking but the DB does the fusing, switching and doesn't need all of the tails. You can specify them with a lockable door too.

Btw once you apply cable calcs you may find that you may need 25mm SWA, and on 100a you would with out doubt need it.