Rcd information

[shakerbess]

hi could anybody please tell me the following thankyou type of protection afforded by the following rcd's and suggest an application for each 30ma, 200ma and 500ma
thankyou

 

[malcolmsanford]

30mA Additonal Protection

200mA Absolutely no idea as I have never seen or used one. Are you thinknig of 200mS?

5oomA Construction sites for sockets outlets exceeding 32amps

 

[DurhamSparky]

sure its not 300ma as that's used for fire!!

 

[shakerbess]

sure its not 300ma as that's used for fire!!

hi thanks for reply yes 200ma i think is to do with if you have high ze you can use as main isolator to protect the board with a 200ma rcd isolator for TT installation i think

 

[GT1]

I seem to remember that question as a straight lift off 2391 but as already said I think the question normally asks about 300ma for fire.

 

[DurhamSparky]

if its a TT type question 100ma used to be used at the front end but now that tends to be by the by now with 30ma on majority of circuits!

 

[Guest123]

I must admit I have never heard of nor seen a 200mA RCD.

In TT installations the usual course was a 100mA time delayed RCD to provide additonal earth fault protection in conjunction with a 30mA RCD which provides additional protection against the failure of basic protection and fault protection.

300mA RCD's are used primarily in agricultural installations and also for protection against fire.

 

[tony mc]

Just had a look at Brian Scaddans book but on Inspection Testing no mention of 200mA.

I would put money on a BS RCD operating at 1x current operating at 200ms or under.

Sure some of the very knowledgable guys on this forum will be able to give a definate answer.

 

[ian1511]

you say 100ma time delay is by the by does this mean its now not required?its just am bout to start a re-wire with a tt supply and am in process of registering with napit and this is a job they will be visiting.

 

[DurhamSparky]

Ensure all circuits are protected by 30ma RCD and you can do away with the 100ma Time delay!

chances are you using a 17th Box with 2x RCD

 

[malcolmsanford]

you say 100ma time delay is by the by does this mean its now not required?its just am bout to start a re-wire with a tt supply and am in process of registering with napit and this is a job they will be visiting.

If the Installation as a front end 100mA RCD and it is in good working order then there is no need to change it, in fact it gives you a few more options on the type of CU etc you can fit.

If it has a front end ELCB then you will have to remove it, and then go either for a dual rcd board or RCBO's

 

[shakerbess]

thankyou for all your in-put to all that replied

 

[Guest123]

This is a little dated (16th Ed) but it does give you some ideas as to what the different ratings of RCD are used for.

As I said it is a bit dated asa the 17th Ed now requires 30mA RCD to a lot more situations.

 

[ian1511]

thanks,can just go with a 17th dual rcd then,100ma time delayed sounds expensive.