Ancient wiring before CU

[NewOrder]

I have noticed a lot when doing jobs (I am a computer engineer but a lot of my work involves telephone wiring and the master socket is often next to the CU) that the boxes before the CU are 1930's in design and really really ancient. I assume they are the step down transformers but are they safe?

I assume they are also out of the hands of sparkies?

 

[Spark123]

Do you mean the service head before the meter?
These are DNO property and should just have a fuse in them - out of bounds to everyone bar the DNO.

 

[NewOrder]

Yep thats the one. The wiring in them also looks 1930's and it just seems like its a possible point of failure? I am surprised the service companies don't upgrade them when they change the meters but I guess its a big job. The one I saw today had a wire going into the meter that looked more like it belonged in an Austin 7.

Our house was built in 1906 and was told it had electricity (lighting) from the day it was built, but the main fuse is quite a modern unit with nice 420v warning stickers all over it!

 

[Spark123]

420v could be 3 phase, then again it might just be an insulation rating.
I don't think the meter changers are allowed to work live to change the service head, probably outside thier scope of work. Think there is a member called Roo on this site which does meter changing.

 

[NewOrder]

Why would it be three phase just NORWEB preference? It just something I have always wondered about, my mate had a problem years ago in his house that the lights kept flickering, he noticed smoke comining from one them fuses and the electricty board rewired the lot before the CU.

 

[Spark123]

If there is a 3 phase supply to the property then they will probably install a 3 phase head, even if only one phase is in use.
Then again, if they only have a 3 phase head in the van and the nearest stores is miles away they may just pop it onto a single phase.
Made the mistake of calling a DNO fellow the other week Norweb, he said they haven't been Norweb for years!

 

[GT999]

a little off topic then (sorry)

but the company fuse holder at my service head, says "80amps, 415v AC".
its a modern-ish house with what looks like a TNCS arrangement.

so the stupid question is...... is my mains is 230volt ac ?

im assuming as said earlier in this thread, that the text on the fuse holder is more a specification than the actual supply..?

the house is about 15yrs old. Phase and PEN come into the service box from underground...

 

[Spark123]

If you only have one fuse holder then it will be the normal 240v (or 230v) service.
It might be that the fuse holder is rated to 415v, there are 3 fuse holders where 3 phase is available.