Rcd as main switch and boNding q

[Davey1988]

Ive read many of times and ill probs get shot of abuse for asking but am icorrect in saying rcd not allowed to be a main switch unless a rccb?

also another question is equilpotential bonding to pipe 1 then link to pipe to pipe 2. Is this a equilpotential bonding link? Or is supplementy only if you link 2 pipes which are all ready bonded. Weird one for me.

 

[D Skelton]

An RCD is allowed to be a main switch.

A bond between two extraneous conductive parts is a supplementary bond.

 

[Davey1988]

Ah i see, i read a sticky post which said rcd cannot but was 2009 (throught may of been updated)

So what your say is any bonding for gas and water is equilpotential no matter how many pipes need interlinks, and any other metallic parts in the ground is supplementary.

 

[D Skelton]

Ah i see, i read a sticky post which said rcd cannot but was 2009 (throught may of been updated)

What is the link to this post? I'd like to check it out.

So what your say is any bonding for gas and water is equilpotential no matter how many pipes need interlinks, and any other metallic parts in the ground is supplementary.

What I'm saying is a main protective bonding conductor links any incoming extraneous conductive parts to the origin of the installation (the main earthing terminal). Any bonds between extraneous conductive parts are supplementary.

The cable that links your MET to your gas meter is a main protective bonding conductor, the cable that links the pipes underneath your boiler or links your bath taps to your basin taps is a supplementary bonding conductor.

 

[guest119]

Looks like you are educating a Electrical Trainee here D.

Boydy

 

[D Skelton]

Looks like you are educating a Electrical Trainee here D.

Boydy

I'm in a charitable mood!

 

[Davey1988]

http://www.electriciansforums.co.uk...m/6334-useful-information-working-sparky.html

few lines in to the main post.

Can all earth go to the met as i see earthing blocks near cu. is their a preference to earth as not specified in the osg.

 

[markc123]

Daydie, genuinley purchase GN8 - it's actually pretty good.

I'm not trying to be funny, just helpful - make it your bedtime reading for the next few months. Price is abit dodgey, as are all IET publications but worth it imo.

 

[D Skelton]

http://www.electriciansforums.co.uk...m/6334-useful-information-working-sparky.html

few lines in to the main post.

Can all earth go to the met as i see earthing blocks near cu. is their a preference to earth as not specified in the osg.

If I'm right I believe 314.2 is the one about division of circuits. One circuit going down shouldn't affect any other circuit blah blah blah...

Yes this is true, but this doesn't mean you cannot use an RCD as a main switch, it means you cannot use an RCD as a main switch if the faliure of one particular circuit will make that RCD trip.

 

[Davey1988]

Thanks mark i will have a look into it.

D, any circuit has the potential to trip and rcd, so would best practice not to use the rcd as a main switch but last resort you may? As they trip all the boad anyways or half if new board.

 

[Richard Burns]

The reason for not using a single RCD as the main switch is stated because there is a requirement to prevent nuisance tripping where a fault on one circuit takes out another, however this is only where it may cause danger, which it will not in most domestic situations (to some extent).
The designer would need to take this into account if they were to use a single upfront RCD, electrically no problem, nuisance wise, can be a problem.

 

[Jay Sparks]

If I'm right I believe 314.2 is the one about division of circuits. One circuit going down shouldn't affect any other circuit blah blah blah...

Yes this is true, but this doesn't mean you cannot use an RCD as a main switch, it means you cannot use an RCD as a main switch if the faliure of one particular circuit will make that RCD trip.

I did an EICR a few years ago and instead of a dual RCD board, there were TWO cu's, both with an RCD main switch. The circuits had been split accordingly but what a waste of money!!

At the OP, there is a table in the on-site guide that has different types of switches etc in it. Have a look for BS EN 61008 and see what it says about being used as a switch. But as others have said, its not good practice to just use one for all.

Jay

 

[DPG]

If I'm right I believe 314.2 is the one about division of circuits. One circuit going down shouldn't affect any other circuit blah blah blah...

Yes this is true, but this doesn't mean you cannot use an RCD as a main switch, it means you cannot use an RCD as a main switch if the faliure of one particular circuit will make that RCD trip.

Which it would if an earth fault occurred on any circuit in the house and there was a 30mA rcd main switch. Daz

 

[Davey1988]

Ah clears that up, thanks guys

Rather ask you all silly questions than be a dodgy sparky which aint 100%

communication is king

 

[GLENNSPARK]

Ah clears that up, thanks guys

Rather ask you all silly questions than be a dodgy sparky which aint 100%

communication is king

so`s competency...

which you cant be if your asking dull rubbish like this...