Circuit Breaker inline with another Circuit Breaker

[magicnumber6]

I recently moved into a mobile home, and I am questioning the electrical installation that was done. My main question is can you have a circuit breaker inline with another?

The electrics consist of the main supply into an outbuilding which has a meter, then a main off/on switch connected to an 45amp circuit breaker. From this breaker the cable runs into the mobile home (armoured) and goes into a hager consumer unit, which is a split device (one side breaker and the other RCD). My question, is this persmissable, i.e. a circuit breaker in line with another breaker?

I have noticed on the occasions that the electric has tripped, say the kitchen ring main, none of the breakers trip inside the hager unit (i..e none flip down), BUT the one outside is flipped??

Have I inherited something dangerous?

 

[Spudnik]

Not always.

It sound like you have RCD's inline, which TBH is not good, reasons being you are finding out now.

It could also be the fact that you are overloading the 45A MCB thats protecting the supply.

A few pics may help.

Oh and welcome.

 

[i=p/u]

breaker goes when overload, maybe you paying for somone elses electric too. could be a few things.. il wait see how proffesionals approach

 

[Deleted member 9648]

From your description it sounds like a 45a supply into a split load board in the mobile..(some of the circuits in the mobile rcd protected some not)...Nothing really wrong with that except that ideally all circuits should be RCD protected (depending on the earthing system),but if the 45a mcb is tripping occasionally at the intake you may be overloading it....TBH 45a is not a lot for a mobile supply.A few heaters,oven,kettle etc and you will be over.
All that said though it's impossible to provide a diagnosis from a PC,I would suggest you employ a reliable electrician to take a look.

 

[SirKit Breaker]

Is the on/off switch at the 45a circuit breaker a RCD main switch, or just an ordinary red on/off switch? If it is a RCD then check its mA rating, if it is 30mA, and the one in the caravan consumer unit is also 30mA then you will get problems due to discrimination. There are a couple of very easy and cheap fixes. These fixes however are not a DIY job, nor can it be done on a forum. You will need a proper assessment of the current set up, and the correct test gear to ensure that once fixed, it is also safe. Caravan supplies fall under BS7671. I would advise you to get an Electrician in. I assume by the content of your post that you are not one. If the set up is different than how interpret it, then you may have a more involved problem that needs sorting out.

Cheers......Howard

 

[IQ Electrical]

Has the installation been inspected at any point?
I would call an electrician, tell him your concerns and let him recommend a course of action-maybe a Periodic Inspection to assess the installation against current requirements.

MCB's can also be troubled by external influences in external situations, damp, cold, condensation etc.

 

[Deleted member 9648]

Howard....Mobile homes come under Bs 7671 but not as special locations in section 721,general requirements apply.They are not caravans.
(just thought I'd point that out )

 

[magicnumber6]

Managed to get some photos. The 1st showing the conssumer unit arrangement, the MCB here connects to the inside of the home to the other hager box. So as I was describing it seems I have MCD inline with other MCB/RCB's - is this ok. The history, is that the previous owner gave me an electrical inspection certificate and all it says is faulty earth on light main, (so I will need an electrician to check this out), but in mean time is this set up ok?

 

[rryles]

Well - there are far more experienced people than me on here, but even I can see a couple of faults already. Not the worst install, but worth getting an electrician in to check.