Weekend Quiz

Good morning ebee,

                                      I have writer's block today, but I will ask a question based upon a recent installation that I saw.


You visit a 1950s bungalow. You notice an original wooden cased four way fuse box with porcelain fuse wire holders, all in good dry condition. The final circuits are 30Amp cooker, 30 Amp sockets, and two 5 Amp lighting circuits. The fuse box is supplied by what look to be single insulated, or quite small compared to moderns standards, red and black tails from a Voltage operated earth leakage circuit breaker. The black cable  V.O.E.L.C.B. connection to the original earth rod has been disconnected. The test button of the V.O.E.L.C.B. does not cause the unit to trip off. The cooker panel has a 13 Amp socket mounted in it. Zs at the cooker panel is 0.25 Ohms. The supply is P.M.E. All cables are P.V.C. insulated.


Is this installation safe for continued use?


Z.

No

Not enough information...

the original earth rod has been disconnected

 

The supply is P.M.E.

Is the installation utilizing the supplier's earth, or is the installation unearthed?


Otherwise, plenty of C3s I imagine - no RCD additional protection to indoor sockets, lighting circuits, concealed cables and so on; probably no c.p.c. on lighting circuits, but provided there are no exposed-conductive-parts that's still only a C3 for me. Bathroom situation will need some careful looking at - but If it's all-copper pipework it'll probably satisfy the requirements for supplementary bonding between extraneous-conductive-parts and if there are no exposed-conductive-parts (typical batten lampholder with a HO skirt and a plastic pull switch setup) than I can't see anything beyond a C3 there either.


A probable C is lack of RCD additional protection for portable equipment outdoors - so if there's a garden (and no RCD sockets marked 'for equipment outdoors' lurking somewhere) that would be a C2 for me and hence an unsatisfactory, but if there aren't any gardens, or perhaps just communal gardens that are maintained by contractors, maybe that's not a fail either.


Size of tails will need checking (possibly against supplier's fuse - for that age anything down to 30A might be possible). If the tails really are unsheathed PVC (seems unlikely) then they might be a C2 - but accessibility needs to be taken into consideration - if they're within an enclosure that only gives access by means of a tool or key then they probably don't need a sheath to comply with the letter of the regs - it has even been suggested a meter box meets that requirement!


   - Andy.

I would question 30 amp fuses in a 1950s vintage wooden box  my nan had one like it in her bungalow wired in 1947 when she bought it and the maximum fuse size was15 amps for a socket in the kitchen all others were 5 amp. Incidentally the main box had no switch this was a separate metal clad job fitted with a 60 amp fuse

Satisfactory is not what Zoom asked. He asked if it was safe. Hence my one word answer - no