Distribution Board and Sub Distribtion Board

observer2u

I have a very old house that has been extended over the years. I have 2 distribution boards and now am in the process of extending my home. We don't have enough free circuits to tap into and the extension seems to be overloading the system anyway causing it to trip numerous times.

What are my options here. Can I add a sub distribution box to take the extension and will this be of any benifit or will it still overload the exisiting system??

Any electricians advice would be very welcome. I want to avoid having to completeley strip down the exisiting system and put in new fuseboards!

Thanks

M cebee

the 'supply capacity' and your 'demand' is what's important

basically you need to check existing supply and see if you need an increase in 'capacity' taking into account the new work as well

DublinDilbert

Post pics of the existing board and list off what circuits / loads it currently feeds.

If the wiring in the rest of the house is ok and depending on the location/size of the extension it might make sence to use a sub board.

If the current board is tripping like you say, you should address this issue first. Maybe upgrading the main board would fix the current problem too.

M cebee

if the capacity's ok-everything else like sub-mains and boards can be sorted out

sounds like an undersized sub-main or even an rcd tripping

observer2u

In what instances does it make sense to use a sub board. Given that the existing house already has 2 boards operating - is it gettin messy to add another one. The existing house was working fine before we added the extra load but I suppose what my question is - will a sub board allow the extension to operate on its own set of circuits and the existing house to operate as it did before?

observer2u

In what instances does it make sense to use a sub board. Given that the existing house already has 2 boards operating - is it gettin messy to add another one. The existing house was working fine before we added the extra load but I suppose what my question is - will a sub board allow the extension to operate on its own set of circuits and the existing house to operate as it did before?

I don't have any pics to hand sadly. Can get some tomorrow

DublinDilbert

Can you post a pic of your existing two boards?

Others can correct me if I'm wrong, but sub boards are typically used to simplify the layout and number of cables that need to be pulled to one location. Usually used in comercial / industrial or large domestic set ups. It will all depend on the size / location of your extension.

Bruthal

Yes they would be used where the installation covers a large area, to simplify the circuit runs, and to enable them to have low loop impedence etc at the final circuits.

As an example, rather than run 70 meter socket circuit runs to the far end of a large installation, a sub board would be better down at the far end of an installation with a proper sized sub main, and then the socket circuits would be much easier and shorter. As well as lighting, and other services.

It sounds like possibly the wiring installation is old also in this house, and circuits added in were doubled or trebbled up onto existing fuses/MCBs, and so tripping circuits. Was it ever rewired in recent times?

M cebee

saves running all the final circuits back

voltage drop and loop-impedance is lower

tripswitches are close to circuits protected