DNO Query

[JackTheCat]

I have a rewire to do next week.
The electricity board have condemned the property and pulled the fuse, before doing that though they have upgraded their side of the installation.

I have not made any enquiries as yet to this, so im asking a few things before being pre informed.

1) Do i just do my side of the install and then liase with DNO during/afterwards?

2) Is there a set procedure/timeframe that they have to work to?

 

[JohnD]

You might consider doing a minimum install, with a 100A DP isolator (very handy!) with 25mm tails, a nice big MET, and a small CU to give you working lights and sockets. You will probably have to upgrade main bonding but then the supplier should be willing to reconnect you. With the isolator you can later add your own henleys and do whatever you like without needing them again.

You can get the installation wall ready with a roomy flame-resistant board (e.g. laminated worktop) spaced off the wall, clean and dry. Although the board is not essential it is a better surface to fix things to than drilling and plugging crumbly old brickwork several times.

If you get an appointment and fail to be there they will charge you £60 or so.

 

[JackTheCat]

john
thanks for speedy reply
have not had a in depth look at job yet, but i did see a Brand new DP fitted by dno, no bonding anywere in house.
PS Customer moved out, so i can work at my leisure...lovelyjubbly

 

[Lectrician]

I hate additional isolators at origin.
I hate MET's external to the CU.
I hate CU's mounted on wood.

If the house is being renovated, the DNO is very unlikely to agree to connect a PME earth at that point. They will provide a TT system until you have completed the works.

I would personally just do the install, with ot with-out a temporary site-supply, and then present the DNO with the tails and earth - send of the completion form (the type from the DNO), and pay the £24 connection fee.

No crappy MET on the wall, No crappy DP isolator, No ****e piece of wood.

 

[JohnD]

hello, Lectrician, thinking about your hate objects, I picture your installations as elegantly simple when they're new; but why don't you like the supply isolator?


I can see the mounting board will seem less necessary today than it will in twenty (or fifty) years time, when the installation will have had odd bits tacked onto it for (e.g.) the IP remote controls; the shed supply; the caravan outlet; the charger for the electric car; the input from the wind turbine; the additional RCBO circuits because split-load boards have gone out of fashion... who knows what? When we look at old installations today we chuckle at the simple electricians of the past, with their ironclad switches and cloth-covered rubber cables; and no doubt in the future, todays plastic split-load CU with its hot tails will also look antiquated and inadequate.

 

[Lectrician]

I just feel simply, that once you have a CU installed, you are not going to need to isolate it for a long while - not really until you need a new CU.......a long way off.

It's another something to go wrong, and get in the way. How about we install an isolator to isolate the first isolator incase we need to service this

My DNO is happy to let us pull a fuse to do work, as long as we send in a COC form to them after...and pay the £18 for earth connection, or £25 for tails aswell.....if appropriate.

If you need to add more stuff around the CU, you can still fix this to a wall.....rather than some unsightly wood.

Our CU's will no-doubt be outdated and laughed at in the future - and so will the wooded board.......If t hey replaced the CU, they probably would the wooden board - I know I do when I rip out a multitude of smaller wylex boards.

It's horses for courses really - I prefer a simple install, with lets bits and bobs. It's still expandable - more so really, as you have taken up less space

 

[ebee]

So you`ve really flat dry walls there? Wooden board and a seperate MET are a must

 

[RF Lighting]

Why do you need a seperate MET these days? The boards I fit have plenty of terminals on the earth bar for connection of main bonding wires etc.

 

[JohnD]

You're not wrong, I'm thinking about the passage of time, when you get Henley blocks, or an additional baby CU for a shower, shed or pond, and the original tidiness starts to be lost. I like to be able to see it.

 

[plugwash]

shower CUs connected to henly blocks are typically used for one of 3 difficiancies

1: inadequate space, this one can be solved just as easilly by moving smaller circuits onto a 50A submain.
2: inadequate incomer (should be a non-issue with modern boards if you use a 100A incomer as most big split units do)
3: inadequate RCD, this is just as easilly solved with seperate RCD protection.

yes shower CUs have thier place on old installs where number 2 is true or both numbers 1 and 3 (or all 3) are true but i can't see any compelling reason to use one on an install with a modern CU and when you count the extra cost of the isolator (to give a single point of isolation though most people don't bother) they probablly aren't financially sane either.

actually there is one sitution i can think of where they have a place and thats where you have a couple of showers and a normal domestic install on a 3 phase head/meter and don't wan't to bother with a 3 phase DB, you can put each shower and its associated lighting circuit on a shower CU on its own phase and then put the main CU on the remaining phase.

 

[RF Lighting]

But how often do you fing a true domestic setup with a 3 phase supply and a 3 phase meter?

I've seen a few with 3 phase service heads, but they have always had 2 phases unused and a single phase meter fitted.

Who is going to use 300A in a domestic situation?

 

[kai]

Not likely to find three phase in a house, you are more often likely to find a service fuse block with two or three fuses in it, to feed separate flats in a converted building.

 

[Steve]

Who is going to use 300A in a domestic situation?

somebody who likes to be very very warm . . . . or very very cold . . .

Personally, I would ask for the upgrade if i saw a 3 phase head in my house, since i could have one of those fancy 3 phase air con / Ground Source Heat Pump units then, which i am led to believe are more efficient than single phase ones.

Whats the going rate to connect the other 2 phases and fit a new 3 phase meter?

 

[Lectrician]

So you`ve really flat dry walls there? Wooden board and a seperate MET are a must

Don't get me wrong - If it needs a board due to a REALLY ****e wall, I would use one. I would never use an MET.

On a new build, renovation etc, there should always be a good wall to fix to. Nice clean lines. What with the CU supposed to be sitting at the accessibility height, and not stuck under the stairs or above the front door, it will no-doubt be on view. Some companies here are starting to use flush CU's with the larger front covers.

 

[RF Lighting]