Do 100ma RCD's need replacing with 30mA?

[eddyfeakes]

I am going to do a Periodic Inspection of a large old restaurant, and whilst have seen that on a couple of the CU there are 100mA RCCB only. Will I have to insist that they are upgraded to 30mA? The system is TN/s.

I only ask as I know that the requirements for existing installations do not always match those for new installations and don't want to quote for work that doesn't need doing.

Thanks in advance,

Edd

 

[sparkytim]

Hi Edd

You as the inspector have to make a judgement on these things based on a good understsanding of the current regs (BS 7671 2008 17th Edition) .

For instance you should know what the requirement is for 30 m A RCD protection and the exceptions allowed for in the regs.

Does this installation fit any of the exceptions?

Its Your report so its down to you to decide what recommendations to make.

Have You looked at the ESC Code of practice for PIRs? It will assist you to decide what the codes really mean and gives some examples.

 

[spinlondon]

There is no requirement for 100mA RCDs to be changed to 30mA RCDs.

There are requirements for some circuits, some cables and socket-outlets to be protected with 30mA RCDs.

There are as sparkytim has stated exceptions that can be applied to the requirements for RCD protection.

These exceptions apply to cables concealled in walls and to some socket-outlets.

 

[eddyfeakes]

Cheers both of you. Have not checked the esc code of practice so will look that up. My instinct is to recommend 30ma on all the circuits as the installation is old and it is a restaurant so lots of people around the electrics, not to mention beer! Thanks again

 

[Mark2spark]

Don't lose sight of what you are actually doing.

You are providing a report on the existing installation and it's compatability with current standards (ie 17th edition)

Therefore 100 mA circuits won't be up to scratch, but that doesn't mean that they MUST be replaced.

It's a code 4, doesn't comply, and there's no room on the PIR to 'recommend' 30mA changes.

 

[netblindpaul]

Mark2spark,

I would like to know why RCD's are required on any circuits which are in a commercial/industrial environment?

There are other requirements at work here.

The sockets are NOT for use by ordinary persons.

Paul

 

[Mark2spark]

Paul, I've given a generic answer based on the limited info available.

There might be a flat above, or B & B, who knows.

I understand the skilled person argument.

Mark.

 

[netblindpaul]

Fair cop, but the OP states a commercial premises only!

Paul

 

[Mark2spark]

But we don't know *why* rccb's (100mA or otherwise) have been fitted in the first place, so some conjecture is required?

 

[netblindpaul]

Well TNS so should be no need for rcd to meet Zs.

IIRC no requirement for 100mA RCD in regs for additional protection previously (14th, 15th 16th).

With the info we have I don't believe that a correct conclusion can be drawn?

Paul

 

[Mark2spark]

No, quite.

But rather than not answer...

I was second guessing that the (user of the) rcbo circuits are perhaps for kitchen sockets that for *some particular reason* cannot be supervised and that RCBO was the designers way round it (CDM)

But y'know it could just be "we ran out of mcb's so we used rccb's cos we had a couple spare" scenario.... all for the PIR'r to pass judgement on possibly with the aid of a couple of non-committed pointers from us guys?

 

[septiclecky]

When carrying out a PIR the is NO LEGAL requirement what you put on the Observation/Recommendations the building owner has to have them done.

 

[Mark2spark]

I would like to know why RCD's are required on any circuits which are in a commercial/industrial environment?

I didn't say that they was?

I confirmed (hopefully) that they don't comply?

The fact that they exist is another matter.

 

[sellers]

RCD's are not exempt from commercial/industrial premises!

There are plenty of situations where RCD's are needed, its just not as strict as dommestic installations.

 

[septiclecky]

The regs are for all types of electrical installation domestic/commercial/industrial

 

[netblindpaul]

Well in an industrial/commercial environment the installation is supervised by a duty holder, and is covered by statutory legislation - EAWR89.

Thus the socket outlets are in control of the duty holder, thus are not for use by ordinary persons, thus do not need to 30mA requirement of the 17th.

The OP suggests that the restaurant is old, thus probable that the design was undertaken prior to CDM implementation, there are many such installs around.

On a TNS I can't immediately think of many requirements for RCD's in a commercial/industrial environment.

S.O. for use outside the equipotential zones.

Where Zs cannot be kept low enough, probably rare to see in Ind/Comm due to genreally more robust supplies of larger capacity.

You may come across buried cables that may require protection.

However, a single board wide RCD could cause more problems than it cures in an Ind/Comm install, lack of discrimination in the event of a fault could cause serious business disruption.

MIND! I always talk customers into fitting RCBO's on 230V a.c. 13A s.o. as you never know where they will be used. An up front 30mA RCD on a 24 way 3ph board feeding CNC machines, lighting, s.o. & conventional machinery could be an issue!

The one notable requirement is the 300mA requirement for external influence BE2.

Excluding Agri/Horti here for now.

Paul

 

[Nicky Tesla]

100mA and 500mA RCDs will also reduce the risk of fire.