Old Flat Conversion Wiring

[Steve003]

Hi, This my first post as I qualified last year and I have been picking up small bits of work, Consumer Unit changes and certs etc. However, recently I came across a situation I have not experienced before and would welcome your views.

The house converted into 4 flats probably in the 70’s-early 80’s. The incoming supply was three phases each with a 100amp BS1361 type fuse. From the supply fuses there appeared to be16mm Flat Twin & Earth running up a cavity through various walls to a consumer unit in each of the floor flats, 2 down stairs and 2 upstairs. Each of the Consumer Units had a 100Amp 30MA RCCB feeding the various circuit MCB’s.

Also, although the Gas pipe was bonded where it entered the building it appeared the Protective Bonding Conductor connected to each of the Consumer Unit MET’s was from a gas pipe which surfaced briefly outside the door of each flat.

I realise the line conductors need to be sized on the prospective short circuit current and the CPC sized to the adiabatic equation, but the sizing of the conductors and the physical protection of the cables appears inadequate at first glance, but as not come across this type of installation before I would welcome your views.

 

[Leesparkykent]

A lot more info is needed.

 

[davesparks]

The house converted into 4 flats probably in the 70’s-early 80’s. The incoming supply was three phases each with a 100amp BS1361 type fuse. From the supply fuses there appeared to be16mm Flat Twin & Earth running up a cavity through various walls to a consumer unit in each of the floor flats, 2 down stairs and 2 upstairs. Each of the Consumer Units had a 100Amp 30MA RCCB feeding the various circuit MCB’s.

what feeds each submain? are they fed from switchfuses or a ryefield board or are they just connected straight off of ISCOs?

Also, although the Gas pipe was bonded where it entered the building it appeared the Protective Bonding Conductor connected to each of the Consumer Unit MET’s was from a gas pipe which surfaced briefly outside the door of each flat.

Of course it does, why wouldn't you expect to see services bonded at each flat?

what sort of work were you doing during your apprenticeship?

 

[Steve003]

what feeds each submain? are they fed from switchfuses or a ryefield board or are they just connected straight off of ISCOs?



Of course it does, why wouldn't you expect to see services bonded at each flat?

what sort of work were you doing during your apprenticeship?

Hi Thanks for the reply.

The sub-mains are connected directly to ISCO's. Ofcourse I expected to see each Flat bonded to the gas, but directly to where the meters (</=600mm) were located on the ground floor, which are accessible. However, I am interested to understand if there was a view that bonding at the gas pipe outside each flat was usual with this old conversions and was acceptable due to the "where practicable" statement within the regs.

 

[davesparks]

Hi Thanks for the reply.

The sub-mains are connected directly to ISCO's. Ofcourse I expected to see each Flat bonded to the gas, but directly to where the meters (</=600mm) were located on the ground floor, which are accessible. However, I am interested to understand if there was a view that bonding at the gas pipe outside each flat was usual with this old conversions and was acceptable due to the "where practicable" statement within the regs.

It's not a 'view' about bonding it is the requirements of the regulations! Within 600mm (or as near as practicable) to the point of entry to the installation. Each individual flat is an installation in its own right and should have all services bonded accordingly withing 600mm of their point of entry to each installation (each flat)

 

[davesparks]

If the submains are not protected by a fuse then yes there is a problem, can we assume there is also no main switch before the ISCOs?

 

[Steve003]

If the submains are not protected by a fuse then yes there is a problem, can we assume there is also no main switch before the ISCOs?

The regs wording is .."Where practicable ....within 600mm of the meter outlet union or at the point of entry to the building if the meter is external". Therefore, is the house "the building" in which case the bonding connection for each flat should be at the meter downstairs or if each flat is "the building" then bonding on the pipe outside each flat appears acceptable. So thanks for your reply which interprets "Building" in 544.1.2 to mean in practice "installation". Which, as you state in your post, would mean the installation complies?