Advice on rewire of domestic lighting circuits
 

Hi guys,
May be doing a partial rewire of a house including a new consumers
unit with slip load RCD protection and the main task of rewiring the
lighting and adding main equipotential bonding conductors ans
supplimentary in the bathroom.
The old lighting circuits both share one MCB of the old MEM push-pop
type and are wired in twin core rubber cable. Intresting feature is
the plateswitches have no backboxes so they really do need this work
doing.
Any advice on how to rewire this lot in a furnished ocupied house
without causing a lot of disruption and damage to decoration.

The exisitng installation has has got a 6 way MEM board with type 1
MCBs and a 2 way Wylex board with a 30a BS3036 for the shower which is
not permitted. Im planning to replace both with a Screwfix special
Volex consumers unit. I shall be removing the boards fuse to isolate
the supply as ive doen it before and have an ERG39 cirtificate anyway.
But the meter is right ontop of the cutout only separate by what looks
to be an enclosure with seals and the new white digital meter ontop.
Ive never had to acces the terminals on these before any tips ? As i
will be replacing the tailings with 25mm2 and a 16mm2 main earth both
tails will firstly run into a DP switch in an enclosure.

Cheers,

Jon.

Advice on rewire of domestic lighting circuits
 

"John Southern" wrote in message
om...
Hi guys,
May be doing a partial rewire of a house including a new consumers
unit with slip load RCD protection and the main task of rewiring the
lighting and adding main equipotential bonding conductors ans
supplimentary in the bathroom.
The old lighting circuits both share one MCB of the old MEM push-pop
type and are wired in twin core rubber cable. Intresting feature is
the plateswitches have no backboxes so they really do need this work
doing.
Any advice on how to rewire this lot in a furnished ocupied house
without causing a lot of disruption and damage to decoration.

The exisitng installation has has got a 6 way MEM board with type 1
MCBs and a 2 way Wylex board with a 30a BS3036 for the shower which is
not permitted. Im planning to replace both with a Screwfix special
Volex consumers unit. I shall be removing the boards fuse to isolate
the supply as ive doen it before and have an ERG39 cirtificate anyway.
But the meter is right ontop of the cutout only separate by what looks
to be an enclosure with seals and the new white digital meter ontop.
Ive never had to acces the terminals on these before any tips ? As i
will be replacing the tailings with 25mm2 and a 16mm2 main earth both
tails will firstly run into a DP switch in an enclosure.

Cheers,

Jon.

You should consider a 6A lighting circuit for upstairs, a 6A lighting
circuit for downstairs and a lighting circuit for exterior/security
lighting. If you are planning mains smoke alarms and burglar alarm, don't
put these on a lighting circuit, put them on their own 6A circuit.

In terms of rewiring without disruption in an occupied/furnished house,
you've got little or no chance of that. Most houses only get rewired when
they change hands for this very reason.

If your attic is not boarded out and not full of stuff, then rewiring the
upstairs lights can be straightforward. If you're lucky, there will be
metal channels between the light switch points and the roof. Use the old
cables to pull the new cables in.

Be advised that it is illegal to tamper with the electrcity board seals.

HTH

Advice on rewire of domestic lighting circuits
 

"Smudger" wrote
| "John Southern" wrote
| But the meter is right ontop of the cutout only separate by what
| looks to be an enclosure with seals and the new white digital
| meter ontop.

Some new incomer termination and service fuse units are designed to
integrate to the meter, to reduce theft of electricity by tapping into the
supply side of the meter.

Unless the meter output tails are accessible without breaking seals, you
really should get the elec co to reconnect new tails for you to your DP
switch.

| You should consider a 6A lighting circuit for upstairs, a 6A lighting
| circuit for downstairs and a lighting circuit for exterior/security
| lighting. If you are planning mains smoke alarms and burglar alarm,
| don't put these on a lighting circuit, put them on their own 6A circuit.

Often better put on a lighting circuit, where loss of power will be noticed
more quickly. Battery back up smoke alarms are mandatory on a shared circuit
though.

Owain

Advice on rewire of domestic lighting circuits
 

snip

| You should consider a 6A lighting circuit for upstairs, a 6A lighting
| circuit for downstairs and a lighting circuit for exterior/security
| lighting. If you are planning mains smoke alarms and burglar alarm,
| don't put these on a lighting circuit, put them on their own 6A circuit.

Often better put on a lighting circuit, where loss of power will be
noticed
more quickly. Battery back up smoke alarms are mandatory on a shared
circuit
though.

Owain

I guess it's a matter of opinion. The On-Site Guide allows either method.
I definitely wouldn't put smoke alarms on a security lighting circuit
though.

The problem as I see it is that often, when a light bulb pops, it takes the
breaker out with it.

So, if you are away from home and have left some lights on (or something
triggers the outdoor security light) and a bulb blows and takes out the MCB,
then your smoke alarms will be off as well.

Of course, if there's no one in to hear the alarms go off, then your house
will burn down anyway ;-)

FWIW, battery backup is mandatory, whatever.

Smudger

Advice on rewire of domestic lighting circuits
 

On a lighting circuit is recommended for all AC alarms with
battery back up; only AC only have to be wired onto thei own dedicated spur.
Though cheaper to buy are more expensive to install in time and materials eg cable.


"Owain" wrote in message ...
"Smudger" wrote
| "John Southern" wrote
| But the meter is right ontop of the cutout only separate by what
| looks to be an enclosure with seals and the new white digital
| meter ontop.

Some new incomer termination and service fuse units are designed to
integrate to the meter, to reduce theft of electricity by tapping into the
supply side of the meter.

Unless the meter output tails are accessible without breaking seals, you
really should get the elec co to reconnect new tails for you to your DP
switch.

| You should consider a 6A lighting circuit for upstairs, a 6A lighting
| circuit for downstairs and a lighting circuit for exterior/security
| lighting. If you are planning mains smoke alarms and burglar alarm,
| don't put these on a lighting circuit, put them on their own 6A circuit.

Often better put on a lighting circuit, where loss of power will be noticed
more quickly. Battery back up smoke alarms are mandatory on a shared circuit
though.

Owain

Advice on rewire of domestic lighting circuits
 

Smudger smudger@here wrote:

FWIW, battery backup is mandatory, whatever.

I don't think it is, for an independent circuit supplying the alarms.

--
Chris Green