Electrics not to standard

bouicca21

My flat was rewired 8 years ago.   I thought that meant all was ok, but no, because according to AdrianC my CU became a fire hazard when the regs changed.  I am steeling myself to face the danger …

AdrianC

bouicca21 said:

My flat was rewired 8 years ago.   I thought that meant all was ok, but no, because according to AdrianC my CU became a fire hazard when the regs changed.  I am steeling myself to face the danger …

I am merely the messenger.

What you meant is "According to the Institute of Engineering and Technology and the British Standards Institute, as adopted into Building Regulations"...

Section62

coffeehound said:

Slightly shocked (heh) to see a fuse board described as perfectly safe.  

Fuses do nothing to protect against electric shock.  

An rcd can make the difference between life and death. 

OP, whatever you do, please get a new consumer unit ASAP

I understand what you are saying, and yes, an RCD can significantly reduce the risk of a bad outcome.

But it isn't true to say that fuses do nothing to protect against electrical shock.

Protection against electrical shock involves many interrelated actions to prevent people and animals from coming into contact with live parts. In a domestic setting with wiring and appliances made to a recognised standard, the risk is largely from something developing a fault, or the user doing something unclever (like chopping the hedgetrimmer cable).

Some faults (e.g. a 'live' wire chaffing and coming into contact with the metal cabinet of a washing machine) would amount to a short circuit, providing the grounding arrangements were working correctly.  In which case (and assuming no RCD) it is likely that a fuse will blow, either in the plug/FCU, or possibly at the consumer unit.  If the fusing arrangements handle the fault before the user touches the metal parts of the washing machine then the fuses have done their job of helping to protect against shock.

In the hedgetrimmer example, if it is a double insulated model there will be no earth wire in the cable. The user should also be insulated from the blade by plastic handles. At the moment the blade slices through the cable there is unlikely to be a reliable path to earth, and therefore an RCD won't necessarily trip. In fact even with RCD protection, the 'live' end of the cut cable could remain live until a path to earth is established for either of the conductors.  However, in cutting the cable the metal blades might (probably will) create a short circuit, which the fusing arrangements should deal with first, again contributing towards protection against electric shock by removing the source of power before a path to earth is established.

RCD's are a really important part of protecting against electric shock, and I wouldn't want to give the impression they are unnecessary.  The point is that they should be seen as part of a system of protection which includes fuses (or MCB's) that each have their own contribution to the whole.

An old style consumer unit can be 'perfectly safe'. And the user can achieve RCD protection for appliances and equipment by the use of plug-in devices or protected sockets.  Replacing an older consumer unit is likely to be a good idea, but it isn't a 'life and death' thing if the user is aware of the limitations of fuses and adopts other safety measures as well - many of which make sense regardless of whether or not the consumer unit includes RCD protection.  E.g. even with RCD circuit protection on the consumer unit I would still use a plug-in RCD using 230v power tools outdoors.

caprikid1

"Thanks everyone for your help.. I'll probably just end up replacing the fusebox and thats it.. the house has been lived in for a while so its fairly safe to say it's safe!"

Unfortunately it's not that simple, in order to sign of the installation of the fuse box I believe he has to sign off everything !. So it could open a can of works.

It is absolutely not safe to say it's safe,  you don't even know for sure no one has had a shock ? would they tell you.

The cheapskate way to impove the situation is to change the plug in fuses to one with Circuit breakers in to replace the hard wire ones I believe. I have had two houses with hard wire fuses, one had the circuit breakers fitted, first time I had any electrical work done it all had to be binned.