New Domestic Distribution Board

ImBoredDotIe

Hi,

Was just wondering what should be done when changing an old fuse box to a new distribution board with MCB's RCD's.

When putting in the new board, if some of the cables are too short, is it acceptable to join them in connectors once they are readily accessible? (In a large plastic joint box to act as a header)

I know its not best practice doing this but theres no need for a re-wire.

Thanks

Bruthal

A few din rail connectors with the propper locking ones each end of them on the rail in the new board can be used if the cables can reach that far and if there is room.

TheBody

Just be aware that in some (usually older) houses people sometimes added in sockets etc by taking neutral from a lighting circuit. This will cause rcd to trip in your new distribution board. Can be a pain in the ass to fix.

2011

Buy a board that is has row more than you need. The chance are all of the cables will reach the top row because they reached the previous fuses.

Use the top row to install DIN rail type connectors. These can be bought for just about any cable size.

In work we generally use Weidmuller

Crossed posts Robbie!

Bruthal

2011 wrote: »

Buy a board that is has row more than you need. The chance are all of the cables will reach the top row because they reached the previous fuses.

Use the top row to install DIN rail type connectors. These can be bought for just about any cable size.



In work we generally use Weidmuller

Its the great minds thing again 2011, as im guessing you answered the OP straight away:)
Yours is an improved version though.

Bruthal

TheBody wrote: »

Just be aware that in some (usually older) houses people sometimes added in sockets etc by taking neutral from a lighting circuit. This will cause rcd's to trip in your new distribution board. Can be a pain in the ass to fix.

Can be fun alright, i had a house before about 18 years ago where the RCD was tripping even with the main switch off after fitting the new board. And a few others with RCD tripping problems.

Bruthal

2011 wrote: »

Crossed posts Robbie!

I know, mad that is.

2011

robbie7730 wrote: »

I know, mad that is.

:D


Here is a picture of a junction box with both 230 VAC and 24 VDC cabling joined using DIN rail type connectors:

ImBoredDotIe

2011 wrote: »

Buy a board that is has row more than you need. The chance are all of the cables will reach the top row because they reached the previous fuses.

Use the top row to install DIN rail type connectors. These can be bought for just about any cable size.

In work we generally use Weidmuller

Crossed posts Robbie!

Thanks for the replies! The din rail option is a good one and better than the joint box idea!!! Fingers crossed theres not too many problems with the RCD!

2011

ImBoredDotIe wrote: »

Thanks for the replies! The din rail option is a good one and better than the joint box idea!!!

It is neat and provides a high quality connection.

M cebee

Theres a guide in back of rules

the board should be dropped to 2.25 going by the book anyhow

M cebee

robbie7730 wrote: »

A few din rail connectors with the propper locking ones each end of them on the rail in the new board can be used if the cables can reach that far and if there is room.

that's the way a lot of the sub-boards are wired where i work robbie

they came pre-assembled with dinrail connectors on the top-row for the final circuit 'live' conductors

prob fairly standard i guess for sub-boards on large jobs

2011

M cebee wrote: »

that's the way a lot of the sub-boards are wired where i work robbie

they came pre-assembled with dinrail connectors on the top-row for the final circuit 'live' conductors

prob fairly standard i guess for sub-boards on large jobs

Yes, I just got this small sub distribution board made up:

Bruthal

M cebee wrote: »

that's the way a lot of the sub-boards are wired where i work robbie

they came pre-assembled with dinrail connectors on the top-row for the final circuit 'live' conductors

prob fairly standard i guess for sub-boards on large jobs

Yea any large boards for final circuits on indistrial sites i ever terminated would be all din rail connectors alright, usually in blocks labeled lighting, general services, power etc, with each block fed from its own main switch on the board.

I used din rail connectors on domestic boards a few times for situations such as in the OP here. Neat and good connections like 2011 said i think.

IrishSparx

heres a problem I have been informed about today by a customer!! 6 downlighters in a living room. one of the bulbs blow every couple of weeks . Lighting circiut trips, but also the rcd trips!! borrowed nuetral?? nuetral from light connected to rcd side may be the problem?? any thoughts??

I havent got a look at it, just somebody told me today it has been happening in there gaf. Saying every cupla weeks that same bulb would go. and with it the rcd trips. just had me baffled listening to it. dat fault would make ya pull ur hair out if it wasn jus as simple as moven the neutral. but u tink if it was anything to do with the bulb blowing then that wud be N/L no earth leakage??

Just wondering if anybody has come across this and if they have solved the problem??

Thanks!

Bruthal

If it was the lighting neutral onto the RCD neutral, it would trip the RCD immediately the lights are switched on.

In certain circumstances a neutral earth fault on a socket circuit can cause another circuit not connected to the RCD at all, to trip it.

Unless possibly the lights are entirely fed through the RCD, and a fault at the particular light fitting is tripping the RCD. See if the lights are working with this RCD left off anyway.

IrishSparx

Thanks for that. I know its hard for me to explain because I havent had a chance to take a look at it yet. But its just been eating away at me all day.

1. The same bulb on the lighting circuit goes at random times over the space of 2-6 weeks.

2. For the lighting circuits, When this bulb blows, every circuit in the house is tripped according to the owner of the house.

3. Therefore I think in a scence you are right that the lights may be on the R.C.D, But I cant for the life of me imagine how/why this could of been done.

4. Also It is a relativaly new build so there was no changes or add ons made.

baffles me to think why that bulb is the only one to blow everytime and what kind of qualified sparks could have walked away from this problem once completing the job.

Funny enough the electrical company that did the installation have gone bust!!

Bruthal

IrishSparx wrote: »

baffles me to think why that bulb is the only one to blow everytime and what kind of qualified sparks could have walked away from this problem once completing the job.

Funny enough the electrical company that did the installation have gone bust!!

This type of think could happen on a perfectly completed installation, we dont know what type of light fitting it is etc. If the bulb does not blow immediately when the installation was first powered up, how would a problem be seen if the proper testing showed all was ok.

Its hard to say what the problem could be without looking really.

IrishSparx

The owner contacted me there saying that when everything does trip..

It includes the main trip switch that trips!! not the mcbs/rcd

The main trip switch is tripping ???? any thoughts?

Bruthal

Would need a photo of whats tripping.

Sometimes bulbs blowing and the filament seems to fall down lower onto the bulb supports and trips circuits. Either that or a faulty fitting itself, an intermittent short in it or something. But would usually just trip the lighting circuit on its own, but not impossible to trip other devices upstream of it.

IrishSparx

More confused to how its effected the main isolator switch... I feel by the time im done with this i will have to be emmitted

evosteo

a lighting circuit should really not be tripping a 63a main fuse, if it is, it will be detrimental to the cable, when you get a chance you should carry out continuity tests between the conductors and also an insulation resistance test (remember to disconnect all bulbs on the circuit). cable could possibly be pinched by RSJ or pipe work in the ceiling that expands and contracts with temperature. could explain the intermitent side of it.

Bruthal

evosteo wrote: »

a lighting circuit should really not be tripping a 63a main fuse, if it is, it will be detrimental to the cable, when you get a chance you should carry out continuity tests between the conductors and also an insulation resistance test (remember to disconnect all bulbs on the circuit). cable could possibly be pinched by RSJ or pipe work in the ceiling that expands and contracts with temperature. could explain the intermitent side of it.

Its unlikely to be blowing the main 63 amp fuse. But can trip MCBs. They said its tripping the main switch, i dont know what they mean there, unless a 63 amp MCB was used as the main switch.

But i cant see it being detrimental to any lighting cable that has the proper MCB protecting it. A direct short on a lighting circuit can easily have currents higher than 63 amp main fuse ratings, but it will be so brief, no damage is done to cables.

A short that trips a 10 amp MCB can often involve currents far higher than the 10 amp breaker, again though, only for very short times.


The first thing that should be done is the light fitting that keeps blowing bulbs needs to be taken down and inspected. Could be heat damage to wiring possibly. Or something wrong at or with that fitting, but its the first thing to be checked i would think.

2011

+1 to what Robbie said

IrishSparx wrote: »

The owner contacted me there saying that when everything does trip..

It includes the main trip switch that trips!!

I doubt that. I would think the owner is just confused.
This installation should have a main switch fuse as it is a new installation. Therefore it could not "trip". Perhaps he means the RCD (or RCBO) and for some reason the lighting circuit is wired through the RCD that the sockets are on.

I have seen entire houses wired through 1 RCD (100mA) or RCBO such as a TT installation. Then a fault with the filament in the bulb as Robbie described could cause the RCBO to operate (see below).

Robbie:

Sometimes bulbs blowing and the filament seems to fall down lower onto the bulb supports and trips circuits

Sometimes one lamp will fail more than others due to vibration, overheating, water etc..

You really need to have a proper look and investigate.

Find out:

1) Exactly what is protecting this circuit -Turn off the MCBs, RCD, everything one at a time to see every device in the board that can isolate this circuit.

2) What else is on the circuit.

3) What type of light fitting it is.

4)Post a few pictures if you can.

5) How is the light installed (the one that keeps blowing)

M cebee

for new installations the 'main ocpd' in the meter cabinet is an mcb

Bruthal

Yea i had mentioned that earlier alright, then edited and forgot to leave that bit:)

2011

M cebee wrote: »

for new installations the 'main ocpd' in the meter cabinet is an mcb

I forgot about that to be honest! You may be right, but I don't think the customer would be aware of that. I would guess that he is only looking at the board.

Let's see what the OP comes back with

Bruthal

2011 wrote: »

I forgot about that to be honest! You may be right, but I don't think the customer would be aware of that. I would guess that he is only looking at the board.

Yea id say your right, was thinking that myself. They seem to be resetting it themselves, likely at the DB. But maybe they do know about the new meter cabinet MCB if fitted. As you say, more info needed. Photos always seem to tell us a fair bit.

Its not actually the OP in this case, its sort of a new problem another poster came in with in post #15.