Cu Change

[NozSpark]

I see that you quoted me in the above post Nicky, but you then went on about if the current installation could carry the alteration / addition.

One thing though, I did mention in that post that any alteration/addition should be done safely,, if you miss off the bonding then IMO the alteration/addition hasn't been done safely and would not be compliant with the regs

 

[Nicky Tesla]

you would have basically swapped a BS3036 fuse for a BS60898 with the addition of a BS61008 for every circuit, plus upgrading the 5419 switch to a 60947-3. That is basically all you are doing when you swap a DB. I would say that swapping those items is pretty safe to me.

would you also refuse to upgrade an MCB for an RCBO on a shower circuit knowing the earthing conductor is a little on the small side?

 

[NozSpark]

Now your splitting hairs,,, changing an MCB for a RCBO with "earthing conductor thats a little on the small side" is not the same thing as replacing a whole CU..

But generally if the earthing conductor and / or bonds are missing or undersized (may need to be calculated using adabatic) then I would include that in my quote

 

[steptoe]

"There's a reg quite early in the BGB that basically says that any addition or alteration to an installation must be done safely and that the current installation must be able to safely carry the alteration / addition."

Can the installation carry the alteration/addition? Yes of course it can, the DB itself does not introduce any extra current.

6mm earthing conductor and 6mm to the earth rod is very likely to be ok anyway on a TT system and does anyone know what the earth rod resistance is anyway?

Supplementary bonding is not even needed in a bathroom with the 17th edition these days because the IEE have complete faith in RCDs now, otherwise they would still insist on supp-bonding.,

Only do what you are paid for and give advice for what else is needed. The tenants may feel that since there has not been a problem for the last 30 years and the fact that many of the other houses down the street are the same without even a new DB then there is no rush to upgrade.

Would any of you refuse to replace an out of date DB in one flat in a block, knowing that all the other flats need their bonding upgrading too because you have seen everybody elses supply in the communal mains cupboard? you could

Only do what you are paid for and give advice for what else is needed.

Binky said "would now install 16mm just becuase the house next door might converted from TT to TN-C-S"

If you are still TT then how will neutral current flow along your earth conductors because being a TT your earth is not connected to neutral.

right up until that line you were getting a scoob from me,

being TT with your neighbour on TNCS which may or may not be PME makes a massive difference,

Nicky, I think a lot of what you say is not only right, but actually very good information, unfortunately its stuff like this that lets you down,

stop and think for one minute how TT gets its earth, also think how PME gets its earth, now think how it 'may' inter-relate.

 

[steptoe]

reading that it sounds very condescending, its not meant in that way, Im sure Nicky knows just as much as me, if not more, maybe we are just the same and come across not in the best way sometimes. :|

 

[Nicky Tesla]

awww not even half a sccob?

 

[Steve3948]

There you go have the one I had taken off me yesterday

 

[steptoe]

awww not even half a sccob?

tell me how TT and TNCS [which may be PME] combine earthing and I'll give you 2 scoobs,

and, Im fairly sure you know, just that you like to stir it sometimes.

 

[Nicky Tesla]

who me? :innocent

 

[steptoe]

no, sorry, I meant Mr Edison, :slap

 

[Nicky Tesla]

through one extraneous and out another in parallel i presume opcorn

 

[steptoe]

through one extraneous and out another in parallel i presume opcorn

you know better than that,

Im not even going to start on that bit part of an explanation,

Im giving you a chance here Nicky, no skin off me,

 

[Nicky Tesla]

if there is an earth neutral fault on the TT could the neutral current from the PME add to the fault? :C

 

[steptoe]

if there is an earth neutral fault on the TT could the neutral current from the PME add to the fault? :C

close, at least you are getting the gist that it 'can' be the same thing,

OK, so thats not strictly a 'proper' thing, but its a close approximation.

 

[paul b b]

Going back to the main points here....

I've been reading and re-reading through all the points that have been posted, i think it highlights how the BGB is so open to interpretation. Both Steve and steps have made very valid points. If regs are regs they should not be so open, guess its the problem with 50 people writing 1 book, its going to contradict its self all over. Though its not going to change!!

And a note to the op...First thing you should look for is the bonding!!! If i had not looked and quoted like you i would take it on the chin and install them and learn from the mistake.

 

[professional]

so you simply not a massive amount of deviations on your cert?

not the sign of a true tradesman IMHO .

its either right or its a bodge.

true, work is short,

do you want me to tell you why?

[bTW, Im OK-ish busy]

When will people realise i.e. it seems to have been missed from their training (if, of course they ever had any ] ) that any form of deviation from regulations box is NOT to be used for things that you can`t be ar**d to do, or you do not know HOW to do?

Deviations are for alternative methods of compliance with BS7671 that MUST be justified by the designer - for which relevant design knowledge and experience are a PRE-REQUISITE.

Therefore, when a deviation is used, the SIGNATURE of the DESIGNER, indicates that they are competent under BS7671 to fully understand the design process and implications of their decision.

Additionally, as deviations are down to the opinion of the designer, it could be argued that INDIVIDUAL must possess relevant PROFESSIONAL INDEMNITY Insurance and therefore meet the T`s & C`s of the policy, which most of you WILL NOT.

Just a thought, of course.

 

[Nicky Tesla]

I put a deviation on my installation cert today " Bonding connection to the gas supply pipe is not accessible"

The bond is there, in the wall. I did a continuity test and got very good results so i strongly believe the connection to be there.

I am not going to make a big hole in the tenants tiled bathroom wall to locate it. It is nothing to do with if i can be ar**ed or not.

It is simply not practicable

 

[OnOff]

I put a deviation on my installation cert today " Bonding connection to the gas supply pipe is not accessible"

The bond is there, in the wall. I did a continuity test and got very good results so i strongly believe the connection to be there.

I am not going to make a big hole in the tenants tiled bathroom wall to locate it. It is nothing to do with if i can be ar**ed or not.

It is simply not practicable

Would it then be acceptable to run a SECOND main equipotential bond from the MET to said gas pipe but connected somewhere accessible - i.e even if NOT within the usual 600mm etc. And just "leave" the hidden one......hidden? Would TWO be a deviation in itself?

 

[Nicky Tesla]

for what purpose..........it doesn't need another one.

 

[ProDave]

....

The bond is there, in the wall. I did a continuity test and got very good results so i strongly believe the connection to be there.

I am not going to make a big hole in the tenants tiled bathroom wall to locate it.

So you disconnected the gas pipe from the boiler and then tested it did you?

Otherwise, the "good results" you got could well be the gas pipe just connecting to earth via the boiler casing and boiler earth.