Landlords test certificate.

[Adam_151]

I'll confess, for about 2 years I had 3 twin sockets around my garage workbench fed from a DIN rail enclosure I put under one of the original sockets on the ring which was fed from a 30A 3036 fuse. I had a 30mA RCD and 16A MCB in the enclosure. Strictly speaking not allowed, but the characteristics of the B16 in reality are not much different from a 13A plug top fuse. 25% of the time a 110v transformer would take out the B16 though.

There is a certain amount of engineering judgement that needs to be applied here I think. But I don't think anyone is going to suggest that attaching a sub main directly to a ring circuit is good and proper practice. I'd certainly not be happy if one of our chaps installed such an arrangement

 

[JohnW2]

There is a certain amount of engineering judgement that needs to be applied here I think. But I don't think anyone is going to suggest that attaching a sub main directly to a ring circuit is good and proper practice.

I would imagine that most people would agree with that (it doesn't feel 'nice'!) - but even that probably really depends upon circumstances. You probably make it sound a little more dramatic than it necessarily is by talking about "attaching a submain". If one 'knew' that that sockets connected to that spur (since that's what it is) were only ever going to supply relatively small loads, and particularly if there were a 20A MCB in front of all the supplied sockets, then, in electrical/ engineering terms, it's not necessarily any different/worse than connecting that spur ("submain") to a double socket, is it?

Kind Regards, John

 

[conny]

WOW! I was reading through this thread earlier and I seem to have opened a can of worms here. Sorry guys.

I also owe you all an apology. I was in the shed this afternoon sorting a few shelves out and had a look at the CU. The sockets are protected by a 16A mcb not a 20A. The original CU was supplied with a 20A & 6A but the 20A has been replaced with a 16A.
Regarding the likely load in the shed. I have a 700w planer, a 1200w radial saw, a 700w bench drill and a Henry vacuum cleaner. So a total load of 2600w not including Henry and I would find it impossible to use all 3 power tools at once.

I have discovered there are 8 double sockets on the ring which are wired using 2.5 T&E. Which socket on the ring the circuit is connected to I have no idea. It could be the first, the third, the fifth, I honestly have no idea how to determine which one. However, the 4.0sqmm is glanded into the external box and then passes directly through conduit in the wall into the back of the socket. There is no connector block inside the external box.

Hope this helps to clarify the situation and help to resolve your differences of opinion.

 

[deadshort]

priceless. O it's quite

DS

 

[JohnW2]

WOW! I was reading through this thread earlier and I seem to have opened a can of worms here. Sorry guys.

No need to apologise - it's not your fault. It takes very little to open those cans around here!

... The sockets are protected by a 16A mcb not a 20A. The original CU was supplied with a 20A & 6A but the 20A has been replaced with a 16A. Regarding the likely load in the shed. I have a 700w planer, a 1200w radial saw, a 700w bench drill and a Henry vacuum cleaner. So a total load of 2600w not including Henry and I would find it impossible to use all 3 power tools at once.

Electrically speaking. that certainly makes things 'even better'.

However, the 4.0sqmm is glanded into the external box and then passes directly through conduit in the wall into the back of the socket. There is no connector block inside the external box.

... and so does that. If the 'spur' to shed is 4mm² all the way from the ring, that does away with some of the dissenting arguments. In electrical terms, particularly given what you say about likely loads, what you have is, as far as I can see, no problem at all - but you'll probably still find people arguing that it might not be strictly compliant with regulations!

Kind Regards, John

 

[EFLImpudence]

I agree that it's fine.

 

[ban-all-sheds]

Think I should change my user name to BBAS as he is getting silly.

No - I am pointing out what the regulations say. I am sorry of you think that is silly, but if you do I think it is you who needs to reflect, not I.

Soon this thread will get locked because yet again BAS will not accept the BS 7671 is a guide

A guide to what?

A guide to compliance with itself?

and errors will always be made between what is intended and what is said

Yes, that can happen

So if you think that they intended that a ring final be allowed to supply more than just BS 1363 accessories, why do you think that for several decades the relevant regulation has only included BS 1363 accessories?

we all realise that we can use junction boxes, and shaver supplies on and from the ring final.

You may not use shaver supplies directly on a ring final. If you believe that you may then please tell us which regulation permits it. If you cannot, then you clearly cannot be correct.

On the information given I can't see any good reason to condemn the work of electrician one who wired the shed,

OK - so you do not see that contravening the regulations and yet certifying that you complied is worthy of condemnation.

 

[ban-all-sheds]

BS7671, like other standards, gives some general principles, and identifies some of the things that are permitted, and some of the things that are not permitted. The regulations do not state that the colour of the outer sheath of T & E may be pink, but that would not mean I couldn't use pink T & E if I had some.

FGS - do you really think that talking about what the regulations say, or do not say, about the colour of a cable sheath is an intelligent and useful contribution to a discussion about the required coordination between conductor and OPD?

 

[ban-all-sheds]

Simple question. Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device? Yes or no?

Given satisfaction of certain conditions, if there is a downstream 20A OPD (or even downstream 20A + 6A OPDs, if CCC is 27A), then yes.

OK.

Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device and there is no downstream protection?

 

[ban-all-sheds]

Quite, and although BAS's view is that one must comply strictly with 'what the words actually say',

IMO a much sounder principle than yours, which seems to be compliance with what you think the words ought to say because you don't like what they actually say.

I believe that it is reasonable (and probably expected) that people will use electrical knowledge and common sense to decide what is sensible, reasonable and acceptable.

OK. So you believe that it is reasonable for people to contravene the regulations because they think it's OK to use what they consider to be common sense when effectively amending the regulations to say what they happen to want them to say.

For example, I personally do not think it makes any sense to suggest that (as 'the words of the regs' might 'actually say') that it is acceptable to use a ring final to supply a load via a 13A FCU, but not via, say, a 10A MCB.

Whether you do or not is of no relevance. The regulations say what they say.

 

[ban-all-sheds]

If one 'knew' that that sockets connected to that spur (since that's what it is)

But it is not sockets connected to that spur, it's a consumer unit. And a CU is not a BS 1363 accessory.

 

[ban-all-sheds]

Hope this helps to clarify the situation and help to resolve your differences of opinion.

The difference of opinion, no, I'm afraid.

The CU could contain a single 1A MCB, and it would make no difference, it would still contravene the regulations.

 

[ban-all-sheds]

If the 'spur' to shed is 4mm² all the way from the ring, that does away with some of the dissenting arguments.

No it does not.

I keep telling you that the size of the spur cable is of no relevance - it's what is at the end of it that is the problem, and it would be the same problem for any size of spur cable.

you'll probably still find people arguing that it might not be strictly compliant with regulations!

Is this term "strictly compliant" a sort of converse to the principle of using the term "slightly pregnant"?

It either complies, or it does not. And this does not.

 

[JohnW2]

Simple question. Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device? Yes or no?

Given satisfaction of certain conditions, if there is a downstream 20A OPD (or even downstream 20A + 6A OPDs, if CCC is 27A), then yes.

OK. Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device and there is no downstream protection?

I'm not sure what sort of satisfaction my answer will give you but, no, of course it doesn't (although, of course, if its the cable of a ring final then Iz ≥ In does not have to "work").

Kind Regards, John

 

[JohnW2]

FGS - do you really think that talking about what the regulations say, or do not say, about the colour of a cable sheath is an intelligent and useful contribution to a discussion about the required coordination between conductor and OPD?

You really can't have it all ways, according to what suits you for a particular argument. If you want to say that the fact that something is not mentioned in BS7671 means that it is "not permitted", then, as stillp says, you would have to agree that pink-sheathed T+E is not be permitted. Those who wrote BS7671 presumably expect that readers will use their knowledge and common sense to realise that, for example, pink-sheathed T+E is not "non-compliant with BS7671" simply because it is not mentioned in BS7671 (which obviously cannot be, and does not attempt to be, "exhaustive").

Kind Regards, John