RCCB as main switch?

[Noob2013]

Hi all,

I have been to a property where the tails come out of the meter and into an RCCB which then feeds the main switch of the consumer unit. All circuits are protected by MCBs.

If I'm adding a new circuit, is it best put in an RCBO instead of an MCB?

Thanks

 

[Simlec]

Noob you still need to answer my question please.

 

[Guest125]

Where does it say that ???

I am so sorry. Got humbled between threads. Sorry guys.

 

[Noob2013]

Should this question not be on the Screwfix forum ?

You would use a MCB. But do you know why ?

I would use an MCB as I believe there would be a level of RCD protection.

Obviously not the best situation as it would take out the whole consumer unit.

I've also read the affects of having an RCBO and RCD/RCCB together.

If I'm wrong, could you please explain?

Much appreciated

 

[telectrix]

I would use an MCB as I believe there would be a level of RCD protection.

Obviously not the best situation as it would take out the whole consumer unit.

I've also read the affects of having an RCBO and RCD/RCCB together.



If I'm wrong, could you please explain?

Much appreciated

ideally, you'd upgrade the board to give circuit division between 2 RCDs or, better still, RCBOs. but you can only do as much as the customer is prepared to pay. in this case, a MCB for the new circuit is the most cost effective solution.

 

[Noob2013]

Can you tell bt the front on an RCD if it is time delayed??

 

[ipf]

I would use an MCB as I believe there would be a level of RCD protection.

Obviously not the best situation as it would take out the whole consumer unit.

I've also read the affects of having an RCBO and RCD/RCCB together.

If I'm wrong, could you please explain?

Much appreciated

Your thinking along the correct lines. We're guessing to some degree as we don't know all the details but it seems ok.....if operation is satisfactory

 

[Guest77]

Should this question not be on the Screwfix forum ?

You would use a MCB. But do you know why ?

HAHA, now that made me laugh, bloody hilarious.

 

[Guest125]

Can you tell bt the front on an RCD if it is time delayed??

It will have a 'S' in a square.

But it if this is installed this will not give your circuit appropriate RCD protection.

whole DB change is what I would recommend.

 

[TJ Anderson]

Can you tell bt the front on an RCD if it is time delayed??

Yes it would be an S type RCD. Also, I can't see on here what rating (ma) the Main Switch RCD is. If it is 30ma then a RCBO (30ma) in series would be rather pointless. If it was a 100ma then it may be required dependant on circuit.

 

[Noob2013]

It will have a 'S' in a square.

But it if this is installed this will not give your circuit appropriate RCD protection.

whole DB change is what I would recommend.

Thank you.

So if the customer would not pay for that, and it was a time delayed rccb, could a new circuit not have an rcbo so it is protected?

 

[Guest77]

Thank you.

So if the customer would not pay for that, and it was a time delayed rccb, could a new circuit not have an rcbo so it is protected?

Noob as you are an apprentice should you be doing this work?

 

[Noob2013]

Noob as you are an apprentice should you be doing this work?

I'm just getting a head start of the situation so I look good ☺

 

[ipf]

It will have a 'S' in a square.

But it if this is installed this will not give your circuit appropriate RCD protection.

whole DB change is what I would recommend.

Not even seen the job and pushing for a db change?

 

[Guest77]

I'm just getting a head start of the situation so I look good ☺

Ah I see, you want to impress your mentor then?

 

[Guest125]

Thank you.

So if the customer would not pay for that, and it was a time delayed rccb, could a new circuit not have an rcbo so it is protected?

Yes you will need to RCBO it. If the main is time delayed you will achieve the required discrimination between the RCBO & the RCCB.

 

[davesparks]

There should not be a 'front end' RCD installed at all. Circuits should be separated so that if a fault occurs the whole installation does not trip.

Your crystal ball is obviously working better than mine! I can't quite see what the earthing system is or what rating that up front RCD is.

 

[Guest125]

Not even seen the job and pushing for a db change?

Come on. It would be the best thing to do.

 

[Guest125]

Your crystal ball is obviously working better than mine! I can't quite see what the earthing system is or what rating that up front RCD is.

I am going on the info I have. As in my signature. Everything I say the installer should be happy within their own mind that it is correct.

 

[Guest77]

Not even seen the job and pushing for a db change?

yup, I was thinking the same, I recommend all old aged pensioners in his area bolt their doors tight.

 

[TJ Anderson]

Yes you will need to RCBO it. If the main is time delayed you will achieve the required discrimination between the RCBO & the RCCB.

As I posted before, It may be a 30ma RCD upfront already, he has not stated rating.