Consumer Unit Without Rcd

[Loobyloobyloo]

Hi all, new to the forum and looking for a little advice.

I am wanting to know what the situation is when adding to an existing circuit (ring main) and (lighting circuit) when the CU has no RCD protection.

I am aware all socket outlets up to 20A have to be covered by RCD protection unless stated in reg411.3.

I am wanting to extend the ring by around 4 sockets and the lighting circuit with a couple of spots.

The work once complete will be inspected and tested by a local electrician and also building inspector will be around, this is where my question comes in,

Do i need to add RCD protection to the circuits i modify (rcbo) and will the rest qualify as the circuit has not been modified or the whole CU want replacing with an RCD CU?

I am confident doing the work stated but from an industrial background, any advice appreciated.

 

[Andy™]

you only need to RCD the part your working on

 

[Loobyloobyloo]

So all other existing circuits will be fine if untouched when inspection and testing is taken out?

 

[Sidewinder]

You can't be responsible for that upon which you have not worked.

Earthing, bonding & the circuits you work upon.

Put limitations for everything else on your certs.

 

[Loobyloobyloo]

Out of interest then,

a cu without rcd protection,

any circuit modified that now requires rcd protection, does rcd protection just have to be fitted on the circuit worked on?

Here stories about electricians not touching circuits unless the cu is replaced to one with and rcd, this is whats confused me...

 

[Sidewinder]

You could, if you were adding a spur to a ring, add an RCD FCU as the spur & run as many sockets off that as a 13A fuse could take and that would be compliant.

There are a LOT of scaremongers out there, and a LOT who have little grasp of the regs and the REAL underpinning knowledge, other than the sample circuits that have been drummed into them on their 5 day course that makes them electricians these days.

Apparently.

 

[Loobyloobyloo]

This is were i don't understand because even then you are still modifying an existing ring main? Yes i understand what you are saying but things are different to what i do everyday, hence why i went on the 17th to try and educate a little more with whats out there...

I want to do the job properly, thats why i am seeking advice to satisfy the regs...

 

[Sidewinder]

You can limit your work to your modifications.

By adding an FCU in a compliant manner to an existing circuit and undertaking your mods from that, would the installation be any less safe than it was prior to the mods?

Bearing in mind, we are talking MINIMUM compliance here.

 

[betty swollocks]

An example of how this, would be the addition of a simple conservatory electrics, an rcd fused spur could be used to protect a number of new sockets in the conservatory, so long as you appreciate the total estimated current draw on these new sockets will be limited to the maximum 13A fuse. The origin of the circuit does not need to be protected as its not your responsibility to do so. As mentioned, the earth bonding to gas/water services DO need to be in place/installed or in some cases upgraded.

 

[Loobyloobyloo]

So an addition to a ring main with an rcd spur running numerous socket outlets would satisfy the regs?

Also back to my original question, if in a situation where a ring had to be extended, an rcbo would be acceptable? Instead of an rcd CU?

Thanks sidewinder appreciated.

Thanks bet.

 

[Sidewinder]

Quite Canoe!

 

[Steve3948]

Ring Mains are not found in houses as far as i know

The streets maybe

:innocent

Just thinking.....

Been in the houses I've done for the last 40 years

Just sayin

 

[SPECIAL LOCATION]

Out of interest then,

a cu without rcd protection,

any circuit modified that now requires rcd protection, does rcd protection just have to be fitted on the circuit worked on?

Here stories about electricians not touching circuits unless the cu is replaced to one with and rcd, this is whats confused me...

Golden Rule No1:-

Ignore here say rumors and misinterpretations about anything...

Verify stuff yourself by reading BS7671 then you wont be working like loads of other cowboys who think they know stuff but actually know jack all!!!!!

Golden Rule No2:-

Regulation 132.16 requires you to verify earthing & bonding and the ensure that the existing installation is of sufficient capacity to carry any additional loading you are putting on it.

BUT....

There is NO regulation saying you must upgrade a CU every time you do any alterations..

There is NO regulation saying you must bring EVERY circuit up to current standards every time you do an alteration...

Golden Rule No3:-

You must ensure all of the NEW work you do is to current regualtions...

Example:-

Widowed pensioner wants 2 extra sockets higher up the wall so he can reach to plug his TV etc into.

Existing installation is BS3036 wire fuses NO RCD protection anywhere...

There are some Cowboy electricians who would say wire fuses are illegal and scare the pensioner into having a new fuse box fitted....

reality:-

Table 41.2 Sates BS3036 are still acceptable...

Pensioner hasn't got much spare money but wants his extra sockets done safely:-

fuse box looks like this...



Extra sockets look like this...



All new wiring is surface.. (not actually needing RCD protection)

Both new sockets have RCD FCU protecting them...

Zs 0.50

RCD @ x1 31ms

RCD @ x5 18ms

Ins Res L+N - E >200Megohm

all compliant..

customer happy...

He pays less than £100 as compared to greater than £100 if CU's become involved.

Unless you can point to the reg that States ALL wiring & CU Must be upgraded every alteration..

wots the problem????

Just use some common sense...

Bit of knowledge of BS7671..

And do the best solution for the particular customer...

Some time it IS more practical to upgrade the CU...

But other times its NOT!!!!

Guinness

 

[Loobyloobyloo]

Great example and advice thankyou

Now i undertsnad that only NEW work has to be to new regulations and new work doesnt effect the origin of the circuit. Right?

"Unless you can point to the reg that states all wiring and cu must be upgraded after every installation" was also what i wanted to know..

So back to extending a ring example, when earth and bond also checked, the only option would be to go down the rcbo route to ensure all NEW work is to the current regulations, am i right or wrong?

Thanks for advice.

 

[Sidewinder]

Why should earthing & bonding upgrades require an RCBO?

 

[Loobyloobyloo]

If any new work has to be to 17th like just stated by special location then once a ring is extended how can you ensure the sockets have rcd protection without an rcbo?

I meant verify earth and bond and capacity, special locations no2

Thanks

 

[Sidewinder]

By adding an RCD FCU to the section you work on?...

 

[Loobyloobyloo]

That will be my option sidewinder i was just curious if the load would be greater than 13amp on radial and the ring had to be extended, what the options would be..

Thanks.

 

[Sidewinder]

2 x 13A FCU radials off separate sockets?

Else, IF you actually really modify the ring then RCBO, would be an option, another would be as I have done previously, to fit a stand alone RCD external to the DB & run the socket cct through this.

DB did not have RCBO's, or RCD's (main switch type) available, think 3871 3ph type B DB, of a very old design, not a Stablok though!

 

[Loobyloobyloo]

P

P

Yes thats what i meant earlier, two radials is another option..

Please reply so i can pot a link, need 10 posts haha