New metal 2 way unit fed from old Plastic 10 way consumer - Ok or not ?

[alPudsey]

Hi,

I have just had work done but not sure if this is acceptable as i am having doubts.

I have an existing 10 way 'Plastic' consumer unit, fitted in 2004.
Electrician has now added a new 2 way METAL unit to feed the dormer Ring mains and Lights & the tails are fed to inside the old 10 way (not from a splitting Henley block).

Even if it is correct, would they have to test the old consumer unit and circuits as well ? , as new one is being from the internals of the old one ? Some of the existing circuits did trip a few times when he was working on it, hence why Im asking about 'testing' of old one

Can you feed a new consumer unit directly from the inside of exsiting old one ? If yes, would installation testing have to include the old consumer too or not ?

 

[telectrix]

only needs to test what he's fitted. however, he must also ensure that the existing is safe for continued use.

 

[DefyG]

How do you mean 'from the internals'?
If he has fed the new CU from an existing or spare way, the supply circuit only should be tested not the other circuits on the existing CU.
If 'from the internals' you mean he has connected into the top of the main switch/isolator, not ideal but the main cutout might be providing the OCD for the supply circuit? Again, existing circuits need not be tested.

 

[Taylortwocities]

It depends on what "tripped" when he was installing. All he really needs to check is the EFLI for the circuit and that the MCB for the circuit to the new mini board is correct for the cable. No need to do anything with the exsiting circuits, if no work has been done on them.

 

[MJPD29]

It is perfectly acceptable to feed a small consumer unit off your existing one even if it is plastic and he does not have to test the entire consumer unit, only the circuit he is installing unless otherwise agreed. Without any other details from what you have described I'd say its fine

 

[GLENNSPARK]

The feed to the metal board should be provided with circuit protection via an MCB in the plastic board for a 5sec disconnection time.....NOT from the top of the incomer in the plastic board...

 

[brianmoooore]

The feed to the metal board should be provided with circuit protection via an MCB in the plastic board for a 5sec disconnection time.....NOT from the top of the incomer in the plastic board...

Can't see any problem feeding from the top of the main switch IF the main switch has sufficient capacity for the extra tails, the connection can be made without excessive copper showing and at the same time be secure, and the new tails are sized sufficient for the design load of the new board.
And the total length of the tails from the meter still doesn't exceed 3m.

 

[IAmSparkytus!]

Can't see any problem feeding from the top of the main switch IF the main switch has sufficient capacity for the extra tails, the connection can be made without excessive copper showing and at the same time be secure, and the new tails are sized sufficient for the design load of the new board.

If the meter tails to the plastic DB were 3m long and then you fed another board from the supply terminals of the main switch in the plastic board, could this been seen as having the meter tails being longer than the 3m recommendation from the DNO?

 

[brianmoooore]

could this been seen as having the meter tails being longer than the 3m recommendation from the DNO?

Edited just for you.

 

[IAmSparkytus!]

Edited just for you.

Ahhhhhh you shouldn't have! ??

 

[7029 dave]

My preference when adding additional fusebox/CU is to take from source splitting tails/ Henley block etc, jumping off main DP incomer forget that not for me. As for using a spare way to create sub circuit to a new CU not for me neither.

 

[IAmSparkytus!]

My preference when adding additional fusebox/CU is to take from source splitting tails/ Henley block etc, jumping off main DP incomer forget that not for me. As for using a spare way to create sub circuit to a new CU not for me neither.

Do you provide an isolator for each new board you add in? Or if there's already one fitted after the meter do you use this to feed the Henley blocks first which in turn feed both boards?

 

[7029 dave]

Do you provide an isolator for each new board you add in? Or if there's already one fitted after the meter do you use this to feed the Henley blocks first which in turn feed both boards?

I didnt mention isolators but yes would utilize existing (if one there or fit) on outgoing then fit my henleys so yeah only one to control the additina boards.

 

[GLENNSPARK]

Can't see any problem feeding from the top of the main switch IF the main switch has sufficient capacity for the extra tails, the connection can be made without excessive copper showing and at the same time be secure, and the new tails are sized sufficient for the design load of the new board.
And the total length of the tails from the meter still doesn't exceed 3m.

You should be using phase blocks to split feeders in my book...

I've seen it before and I don't like it

 

[Deleted account]

If the meter tails to the plastic DB were 3m long and then you fed another board from the supply terminals of the main switch in the plastic board, could this been seen as having the meter tails being longer than the 3m recommendation from the DNO?

This 3 meter rule/ reg is often mentioned. There is no reg that states this.
in some cases 10 meters is perfectly acceptable in others it’s not.