2 CU supplied separately in single converted dwelling

[TomTrundle]

Hello All
Noticed on a job today ...
Domestic house which had been converted from two separate dwellings knocked into one.
It still has 2 x CU's and 2 x Meters. about 4 metres apart.

I've got a bad feeling ......
2 x supplies ... 415volts!

I've not come across this before and I'm not sure of the best way to test.
Would like to put my mind at rest.
The owner of property said the conversion is about 12 years old.
Doesn't recollect ever receiving any kind of certification.

Best
Tom

 

[telectrix]

if both supplies are on the same phase, then you won't get 415V. you will probably find that they are 2 separate installations and will need to be tested as such, unless you want to get it converted to a single supply. that will entail quite a bit of rewiring.

 

[Silly Sausage]

I've got a bad feeling ......
2 x supplies ... 415volts!

Time to get the oscilloscope out!
Will the phase rotation test on an MFT pick up if they are separate phases, just on 2?

 

[telectrix]

just use a wander lead and a voltmeter across the 2 Lin supplies. if they are separate phases you'll get 415V.

 

[Hawk81]

if both supplies are on the same phase, then you won't get 415V. you will probably find that they are 2 separate installations and will need to be tested as such, unless you want to get it converted to a single supply. that will entail quite a bit of rewiring.

If he decides to keep 1 supply he can still keep both CU's and bring a new supply cable to the disconnected CU from the still powered up CU. not much of a rewire really.

 

[Brightspark2]

Time to get the oscilloscope out!
Will the phase rotation test on an MFT pick up if they are separate phases, just on 2?

Why not just test the voltage between the 2?...

 

[decolad69]

if both supplies are on the same phase, then you won't get 415V. you will probably find that they are 2 separate installations and will need to be tested as such, unless you want to get it converted to a single supply. that will entail quite a bit of rewiring.

Convert one to a sub-main from the other and have one supply removed ? Obviously use the supply with the biggest load as the main.

 

[telectrix]

If he decides to keep 1 supply he can still keep both CU's and bring a new supply cable to the disconnected CU from the still powered up CU. not much of a rewire really.

thought of that just after i'd posted. original thinking was to rewire circuits from 1 CU to the other.

 

[decolad69]

thought of that just after i'd posted. original thinking was to rewire circuits from 1 CU to the other.

Iam just not fast enoughon the keyboard !!!

 

[telectrix]

old fast fingers here. just wait a year or 2 when the arthritis kicks in ( that's if the altzeimers doesn't get in first )

 

[Guest55]

Why not just test the voltage between the 2?...

i dont understand.....?
;-)

 

[telectrix]

this man does :

 

[Guest55]

mmm , doughnuts.........

 

[Brendan976]

I this a really big house or will 100amp suply for the whole property?

 

[ayjay]

tell him he,s paying the standing charge for 2 meters- you might get the job to fix it

 

[TomTrundle]

Hiya
Its not particularly big ... think it has 4 beds.. just an unusual conversion. A single 100amps supply would be fine.
Thanks everyone for your replies ...
When your out on your own all day its good to chat through a situation sometimes.

As there is no RCD protection present.. if this installation does require alteration then l would remove fuse from smaller supply.
Split the larger supply and from Henley block into RCD then onto other Meter

 

[TomTrundle]

Hiya
Split the larger supply and from Henley block into RCD then onto other Meter

Oooops! l mean CU..

 

[Engineer54]

Why not just leave it as it is?? Has anyone complained about it, or caused any hazards?? NO, then this is basically just you and what you would like to see. Start interfering and it could bring you a mountain of grief on your shoulders!! lol!!