Advice on Installation

[Thomas Connolly]

Hi Folks,

If I'm extending a lighting circuit, (adding two pendants and an outside light) from an existing pendant but the board doesn't have any protection (an old BS3036 fuse board) What's the best way to add RCD protection?

The new cable for the switches can't buried more tore than 50mm deep and I don't want to whack an RCD FCU anywhere as they are quite bulky.

What would be the best course of action to take to install this circuit so it complies with the Regs?

Thanks,
T

 

[45140]

Thanks guys, however I am certain that if the manufacturer can confirm there is no reduction in safety to the end-user, then that could be used as justification that the departure from BS7671 was legitimate when ranked against the likelihood of the circuit being installed by a non-competent person. After all the person has requested the work and so therefore is looking for the installation to be made.

One for tomorrow I think !

 

[Deleted member 26818]

Well the BEAMA handbook is published on behalf of British and European manufacturers.
Companies such as MK, LeGrand Schneider, Eaton, etc.
It appears to state SRCDs and FCURCDs are still allowed.
However the chart used still states 20A for sockets, so I don’t know how much of the handbook has actually been updated, and how much has just been cut and pasted from the old handbook.

 

[ferg]

Well the BEAMA handbook is published on behalf of British and European manufacturers.
Companies such as MK, LeGrand Schneider, Eaton, etc.
It appears to state SRCDs and FCURCDs are still allowed.
However the chart used still states 20A for sockets, so I don’t know how much of the handbook has actually been updated, and how much has just been cut and pasted from the old handbook.

Table 3 in that handbook says that the RCD FCU is not suitable for protecting fixed wiring.

Which is a pain in the rear. Unless I'm missing something.

 

[45140]

Surely the MCB protects the circuit and the RCD the person

In which case the RCD in the FCU is a valid solution as it will undertake that function

 

[Bobster]

Could I argue that a BS 7288 device with the characteristics of 30mA trip current and an operating time of 40ms complies with the tripping characteristics specified for additional protection, yes I could, but could I argue that it a BS 7288 accessory is a satisfactory replacement for a device manufactured to the other standards? I don't think so.

There may be a very valid reason why accessories to BS 7288 are no longer considered acceptable. I don't know enough about BS 7288, BS EN 61008/61009 to argue the **** and complete a valid risk assessment? No, I don't

I think the major difference is that RCD FCUs and sockets have latching capability.

 

[Deleted member 26818]

I think the major difference is that RCD FCUs and sockets have latching capability.

Could you explain what you mean by latching capability?

 

[Bobster]

Could you explain what you mean by latching capability?

Some need resetting every time the power is switched off, others latch on through a power cut.

I'm not saying this makes a difference to the protection that they afford. Just the operating mechanism is different to an RCB foudn in a consumer unit.

 

[Wilko]

OK so why don't we ask the manufacturers to confirm if the same level of protection is provided ?
I am happy to produce a draft RA based on a 5 x 5 matrix which I would happily circulate for review by more competent peers on this Forum. As a member of the IET I could also circulate there for review as well. I am trained in electrical risk assessment ... As you know a departure from BS7671 is permitted if it has been risk assessed.

If you've the time, it would be very useful and much appreciated, thanks .

 

[Deleted member 26818]

Some need resetting every time the power is switched off, others latch on through a power cut.

I'm not saying this makes a difference to the protection that they afford. Just the operating mechanism is different to an RCB foudn in a consumer unit.

DIN rail RCDs and RCBOs in my experience stay closed during power cuts and don’t need to be reset once power returns, would that be latching?

 

[Bobster]

DIN rail RCDs and RCBOs in my experience stay closed during power cuts and don’t need to be reset once power returns, would that be latching?

Yes, my terminology may not be correct but in effect it is doing the same thing.

However the mechanism between the two is different. Non latching FCUs and sockets are built under the same regulations as latching ones. The non latching ones use electronics to keep the contacts closed. An maybe the testing procedure under that standard misses something that for example CU RCBs are tested for.

Like I said, I'm not sure why they are no longer seen as offering additional protection. I don't own copies of the standards they are tested to. Just speculation on my part.

 

[GBDamo]

OK so why don't we ask the manufacturers to confirm if the same level of protection is provided ?
I am happy to produce a draft RA based on a 5 x 5 matrix which I would happily circulate for review by more competent peers on this Forum. As a member of the IET I could also circulate there for review as well. I am trained in electrical risk assessment.

The thing to remember about Risk Assessment is that you are not expected to be right every time. HSE accept that an incorrect judgement could be made, however they would not act against a person who has Risk Assessed because you have acted correctly and done a risk assessment. That is what the Law requires, it does NOT require to risk assessment to be totally foolproof or for your judgement to be perfect but simply that you have carried it out in a diligent way and the assessments made are not negligent. The assessment is precisely that, your assessment of the level of risk and if it is tolerable.

I have had to make many specific localised risk assessments against HV flashovers and HMRI accept them on the basis that the situation has been looked at by a Competent person who has made a judgement. If in the future something was to happen then the risk assessment would need to be changed but no liability under HASAWA would accrue because we can all make a mistake in a judgement. That is why a risk assessment is usually but not always reviewed by another person.

As you know a departure from BS7671 is permitted if it has been risk assessed.

Please re-read your post, which is perfectly correct, and then ask is this appropriate to a jobbing spark selecting parts for some of the simplest jobs in the electrical industry.

Are we really saying that the responsibilities for the failings of the IET, to provide clear and non contradictory guidance, is to be placed onto the shoulders of those at the very bottom on the industry.

To me it smacks of the wrong people sitting on these panels, forget the conflict of interests with manufactures, but people who have achieved at the very highest technical positions in the industry cannot relate to the realities of low level domestic work.

It's almost as if their more interested in demonstrating their knowledge to each other than in producing a piece of work that is suitable for its customers.

 

[sparksburnout]

Please re-read your post, which is perfectly correct, and then ask is this appropriate to a jobbing spark selecting parts for some of the simplest jobs in the electrical industry.

Are we really saying that the responsibilities for the failings of the IET, to provide clear and non contradictory guidance, is to be placed onto the shoulders of those at the very bottom on the industry.

To me it smacks of the wrong people sitting on these panels, forget the conflict of interests with manufactures, but people who have achieved at the very highest technical positions in the industry cannot relate to the realities of low level domestic work.

It's almost as if their more interested in demonstrating their knowledge to each other than in producing a piece of work that is suitable for its customers.

Very well said and articulated GB. I find this thread quite ridiculous to be honest, people need to stand back and look at exactly what the situation is. If it were me being asked to do this job, I would fit the guy an RCD socket without a second thought, before a bloke down the pub comes along to relieve him of his frustration and just bungs an ordinary socket on, with no testing.

 

[Deleted member 26818]

I must admit I believe it’s a mistake.
If the intention were to ban RCD sockets, then why not just change ‘provide socket-outlets with 30mA RCD protection’
To ‘provide circuits supplying socket-outlets with RCD protection’?
I think this is like in the 17th when originally we had to provide RCD protection to all circuits of locations containing baths or showers. Got changed to all LV circuits.

 

[SparkyChick]

Very well said and articulated GB. I find this thread quite ridiculous to be honest, people need to stand back and look at exactly what the situation is. If it were me being asked to do this job, I would fit the guy an RCD socket without a second thought, before a bloke down the pub comes along to relieve him of his frustration and just bungs an ordinary socket on, with no testing.

Today I'm going to be installing an RCD fused spur to protect some exterior lighting, and earlier in the year I installed an RCD fused spur to protect some new lighting internally at the same property. These changes were designed and quoted for last year and as such have to comply with the 17th edition amendment 3, so I'm pretty happy with my decision to progress as planned.

But given all work designed after 31st December 2018 has to comply with the 18th, using RCD socket outlets and fused spurs to provide additional protection is no longer an option since they are not one of the listed standards.

So... in the event that something bad happened and someone was say injured or killed, how would you defend your decision to ignore the regulations by installing a device which is not listed as suitable for providing additional protection?

 

[Bobster]

Maybe someone belonging to one of the scams can call their tech help and ask why they are no longer acceptable.

That'll get them confused for sure.