Sub Meter Protection?

[mossiejdm]

Hi, I have just had a new Crabtree consumer unit professionally installed, 100a main switch, split load 63/30ma RCCB protecting all supplies except lighting. (House built 1960\\\'s)
My query is although the supplier protection fuse is rated at 100A,and fitted between the meter and CU, the suppliers sub meter (ELGEE Type CL7) has 40A max current displayed, how is this arrangement suitable to protect the meter, or is it using a shunt?

 

[Steve]

Are you saying you have a meter, then a mainfuse, then another meter?

There first thing, on the end of the supply cable, should be a mainfuse/cutout unit.

Then comes a meter. These are often underrated, its nothing to worry about to be honest.

After the meter is your setup, and this can vary. Landlords, for example sometimes fit another meter, a coin meter, to charge tennants for their electric. Generally there will be only one meter. Can you post a picture of your setup for us, showing the whole intake, meter and mainfuse area?

 

[mossiejdm]

Hi Crafty, second time posting, have uploaded pic of setup i was referring to but not sure when Diynot.com will upload, soon hopefully.

As you correctly stated, from the main service supply cable is the service fuse, (presumably 60-80A?) then looped to the 40A rated sub meter, then looped to another fuse box rated at 100A on the lid, then tails to the CU.

I have 100main switch, with split load 63A/30ma RCCB, total MCB rating are as follows : 32A cooker, Shower 32A, Sockets 32A,Sockets 20A,Shed 20A, lighting 6A non RCCB protection.

I want to upgrade the existing shower (7.5kw) to 8.5 kw,replacing 32A MCB to 40A?
Given the total load would it be advisable to upgrade the RCCB to 80A/30ma?

In terms of sub meter current can you explain what you mean by underated?

Many thanks for your advice on this one.

 

[breezer]

picture posting is quicker if you use something like photo bucket.

see forum information

 

[RF Lighting]

You can upload the picture yourself by using an image hosting site such as www.photobucket.com


Far too slow tonight

 

[breezer]

too slow RF Lighting, too slow

 

[mossiejdm]

Hi Guys, taken your advice ref photobucket , have posted pic of the the setup via following link....


http://i179.photobucket.com/albums/w309/mossiejdm/Dscn2045.jpg

 

[Steve]

That meter is old. Any dates stuck to it? They are ment to be changed every 20 years.

 

[mossiejdm]

Just legged it out under the stairs and looked, still has the eastern electricity board label saying it was replaced june 85..... wondering why the registered
sparky did'nt flag that up..? who's cost ?

 

[JohnD]

I don't understand why you call it a sub-meter. I can't see that it is subsidiary to any "main" meter.

The Earthing arrangements look poor. I can't see evidence of main bonding and I can't see if there is a conductor sweated or clamped onto the sheath.

The tails into the meter are clumsily terminated.

If you write to your supplier and ask them if they will install PME, they probably will, maybe free, maybe for £50/£100. If you tell them the meter rating and tell them your design current, they may provide you with a newer meter too, and hopfully better tails. there should be no charge for swapping the meter.

You could check the main bonding yourself; whoever fitted the new CU ought to have done it but you are permitted to do it yourself as a DIY job. However, do not try to clamp or sweat anything to the cable sheath, and do not tighten the existing clamp as it may damage the cable.

p.s. is that a lead gas pipe underneath? Is it bonded?

p.p.s. Opinions differ on having so many circuits through the RCD. What are they?

 

[securespark]

It's a bit of T & E, I think, John!

The main earthing conductor seems to be sweated onto the cable sheath & wrapped in tape. They have (very sensibly) abandoned the EC14...

 

[JohnD]

? look at the size of it compared to the T&E top left. I can also see an anaconda bottom left.

 

[davy_owen_88]

Pretty sure it is twin and earth, probably 10mm^2. You can see it's been pulled through a hole and has those scuff marks. And it looks huge because it's so close to the camera:

I don't like the way it's just hanging there though... is it the same piece that is coming from the top of the CU?

Davy

 

[securespark]

? look at the size of it compared to the T&E top left. I can also see an anaconda bottom left.

I can't see any snake's @rses, let alone an anaconda's...


But I would get shot of the DP Henley block, and wire the tails directly into the meter, without stripping back the grey sheath.

 

[mossiejdm]

Hi JohnD, My mistake for referencing to the main meter as sub...just been onto eastern electricity who have arranged to install an updated meter early march FOC..
Presumably they will install a higher rated meter, which brings me back to my original query how the meter rating is calculated proportional to current loading on main circuit,(Is the shunt involved here?)
You are quite correct spotting the anaconda hanging down 10mm T&E, cable run for upgrade 8.5kw shower but not connected.

RCCB is suppling 32A cooker,32AShower (wish to upgrade to 40A 8.5kw) 32A Sockets,20A sockets, 20A shed power.
Non RCCB 6A lighting circuit

Given the total load would it be advisable to upgrade the RCCB to 80A/30ma, or should i go for RCBO given 17th edition looming?

Just one other point, the professional who upgraded the cu and installed equipotential bonding to gas main failed to notice the abscence of main water bonding.. hey ho down to b&q's..