Fitting of Isolator switch for Scottish power to connect to?

[AndyVR6]

I phoned Scottish Power today (my supplier) to arrange to have an isolator switch fitted to the incoming supply of my house in the North West. The guy I spoke to contacted the meter liaison(?) who confirmed that they did not supply fit isolator switches, but will visit to connect up an isolator switch that has been mounted next to the meter by an electrician.

I asked if they would connect to an appropriate isolator switch mounted by myself, but he couldn't find out the answer, or what it would cost to have an engineer visit to make the connection.

Has anyone had an isolator installed via this route, if so what did it cost? Could I mount a 100amp double pole isolator myself, or would the supplier/visiting engineer insist on proof/certification that it was mounted by an electrician?

Cheers if anyone can advise

 

[JohnD]

I will be very surprised if the person calling to do the connections wants proof of who fitted the switch.

fit 25mm tails that will easily reach so he can just connect them to the meter. Make it all neat and tidy.

have a 16mm G&Y earth wire ready as well that will reach their service head from your MET or block as they will probably fix a cover over their terminal.

they do not usually like you fitting things to their meter board but they will usually tolerate isolator, henleys, earth block.

I particularly like the MEM isolator enclosure, as it has a hatch on the load side so that you can open that end only to fix the load tails, without exposing the Supply terminals that are connected to the meter and will be permanently live. The MEM isolators also come with push-over plastic covers for the terminal screw heads. There may well be other brands with a similar arrangement.

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[AndyVR6]

Thanks John, that looks ideal.

Could you tell me where I could purchase the MEM enclosure & isolator from, i'm having trouble finding them online. Is that isolator the type that normally fits on a din rail in a CU?

I've noticed that the main supply fuse in the meter cupboard is missing its seals, it must of been like that for four years or more. When the engineer visits, could he make a fuss about that? the seals on the meter are intact at least!

 

[JohnD]

there will be an electrical wholesaler in your town. he might be at the back of an industrial estate but there is sure to be one. MEM is mostly used by industrial and commercial electricians, not household, it is very good quality and not the cheapest.

The local supplier will be sure to carry MEM as many industrial electricians will insist on it. If he doesn't have this thing in stock he will probably have a delivery almost every day.

Yes, this switch does clip onto a DIN rail and is the same as is used in consumer units. The enclosure is just an insulated 2-way one. The enclosure has a short rail inside. Similar switches and enclosures are made by all brands, but the MEM is the only one I know of with this hatch, which I think is a very good idea. I could send you one but I would have to charge postage plus a few pounds so it will probably be cheaper to get one locally.

The engineer will take the main fuse out before doing the connections, and will re-seal it afterwards. He will probably not complain about the fuse seal being missing. It is more important if the meter seals have ben tampered with. If you can find a bit of old tarnished galvanised wire, or 30A fusewire, and poke it through the fuse seal holes and twist it round, it may look like it was done a long time ago.

 

[Roo]

I phoned Scottish Power today (my supplier) to arrange to have an isolator switch fitted to the incoming supply of my house in the North West.

Where abouts in the north west?

 

[AndyVR6]

I phoned Scottish Power today (my supplier) to arrange to have an isolator switch fitted to the incoming supply of my house in the North West.

Where abouts in the north west?

Manchester.


John, I've tried a couple of wholesalers in my area so far, one doesn't supply MEM gear at all and the other has recently stopped. Let me know your price for sending me both enclosure & switch, my email address is [email address removed]
Thanks.

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[sparkmanc]

Where abouts in Manc are you?

Theres a CEF, and a WF in trafford park.

Theres also a WF in openshaw near the Tameside College, on Ashton Old Rd.

Just the main two I use.

 

[Adam_151]

Theres also a WF in openshaw near the Tameside College, on Ashton Old Rd.

The one thats supposed to be a main branch or something? (and yet still never seems to have what you want )

 

[AndyVR6]

John,

I forgot to ask, what do I need the earth cable for? At the moment there is an earth cable from the service head(terminals not covered) to an earth block, then from the earth block through the cavity wall into the CU.

When mounting the isolator yesterday, I noticed that there was about 2 mm of exposed cable on one of the meter tails where it exits the meter!! At least that will be put right when the isolator is connected.

 

[philiprreeves]

Hi, having worked for the MEB and city council in Stoke many years i can confirm all of the above.

You will have to provide the isolator yourself. The supplier will make a contact between your isolator and their meter/clock. They will not ask you for proof of who installed the device. If you do not have a current test cert. for the installation they may just leave the isolator switched off, which is common practice.

What is also worth noting is that if your consumer unit (CU/mains board) is more than 3 metres away from the metre you will have to install a fused double pole isolator. Either 60A or 80A.

You can get them from Cheshire Electrical Ldt (Congleton) or City Electrical Factors (CEF) Macclesfield, Stockport area. They are all over.

The EARTH: If the electrical system provide is there TNC-S (PME- Protected multiple earthing) Where at the supplies fused cut-out both the neutral and earth are jointly connected together or a TN-S where the earth and neutral are separate. The earthing just being the sheath of the main in-coming cable. Then you will need 25mm L/N tails from the isolator to the CU unit and 16mm Green/yellow earth cable from your CU or MET (main earthing terminal) to the cut-out or the suppliers MET.

To know if your systems is a PME system you will have to do a Earth loop impedance test between your live at the CU and the MAIN earth at the CU. The reading should not be above 0.35. If it's above this and below 0.8 then the system is a TN-S.
Anything above this would indicate TT system (tera-tera) Earthing by means of an earth rod in the ground probably just outside near to the CU position. On this system the main earthing cable can be a min of 6mm with mechanic protection.(conduit or the like protection the cable)

In Staffordshire central networks are re-installing earth rods on all their PME installations due to PME local issues. The rod is used has a back up.

Thanks, Phil

 

[Roo]

Presently Scottish Power will be using the local DNO/Metering (would have thought UU) to do all their work in your area.

They will have their own men in your area very soon (would have thought in a couple of months now).

They can then fit you a switch to save you sourcing one.

So it all depends on how long you can wait for a switch.

 

[davelx]

To know if your systems is a PME system you will have to do a Earth loop impedance test between your live at the CU and the MAIN earth at the CU. The reading should not be above 0.35. If it's above this and below 0.8 then the system is a TN-S.

Incorrect - those are just the maximium acceptable values. It is perfectly possible for a TN-S system to have a Ze below 0.35R. Mine is 0.09R (I'm very close to the sub-station)

To determine which system you have, either ask your supplier or examine the source of the main earthing conductor. If TN-C-S (PME) it will be linked to the incoming Neutral line. PME systems should also have a label denoting this. If TN-S it will be linked to the metallic sheath of the incoming cable.

//www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements

 

[plugwash]

To determine which system you have, either ask your supplier or examine the source of the main earthing conductor. If TN-C-S (PME) it will be linked to the incoming Neutral line. PME systems should also have a label denoting this. If TN-S it will be linked to the metallic sheath of the incoming cable.

Unfortunately that connection may well be hidden in the service head.

There are some models of service head that are definately PME but there are others with a removable link meaning you really can't tell for sure without opening the head (which I don't reccomend)

A better way is to measure both the earth loop at the origin and the P-N loop at th origin, if the results are very close then you almost certainly have a TN-C-S system.

 

[plugwash]

Incorrect - those are just the maximium acceptable values. It is perfectly possible for a TN-S system to have a Ze below 0.35R. Mine is 0.09R (I'm very close to the sub-station)

and equally it is perfectly possible for a TN-C-S system to have a Ze about 0.35, not every supply meets standards you know

 

[davelx]

Incorrect - those are just the maximium acceptable values. It is perfectly possible for a TN-S system to have a Ze below 0.35R. Mine is 0.09R (I'm very close to the sub-station)

and equally it is perfectly possible for a TN-C-S system to have a Ze about 0.35, not every supply meets standards you know

Obviously.