csa of main earth question

[sparkyork]

hi all, just got in from work and cant be bothered looking in the book!!

job today is TN-S with 60A main cutout fuse (1361). 16mm tails and a 10mm earth. i looked in the book a week ago and as far as i can see, if the tails are 16mm then the main earth needs to be 16mm, is the correct?

also on same job, i found that the oil tank dont have a bond on it either, the consumer unit was changed in january this year so i asked customer for the test sheets, had a nosey and all was on there as deviations etc: no fan isolator and some other minor thing, no mention of no bond to oil tank.

can i phone this company up and see if they will sort it out? or ill do it next week meself....or is there anything i can put on my minor works certificates to cover this??

cheers guys and gals

bumpety bump bump

 

[Cirrus]

16mm tails are ok on 60A but I just upgrade to 25mm with a 16mm earth as a matter of course

 

[PAUL M]

ditto.

 

[sparkyork]

ok cheers, will end up upgrading both then, when the main tails are 16mm how small can the main earth be then?

also any thoughts on the main equpotential bonding absence above aswell? might give powerlink electrical a ring and ask em why they didnt install the bonding (and there fully approved as well!!!)

 

[PAUL M]

ok cheers, will end up upgrading both then, when the main tails are 16mm how small can the main earth be

also any thoughts on the main equpotential bonding absence above aswell? might give powerlink electrical a ring and ask em why they didnt install the bonding (and there fully approved as well!!!)

that doesnt surprise me one little bit 16mm.

 

[Cirrus]

Sometimes we just mark inadequate bonding down as a deviation and then it is up to the client to do something about it.

 

[saveloy]

ok cheers, will end up upgrading both then, when the main tails are 16mm how small can the main earth be then?

also any thoughts on the main equpotential bonding absence above aswell? might give powerlink electrical a ring and ask em why they didnt install the bonding (and there fully approved as well!!!)

When the line conductor is less than or equal to 16mm then the main earth csa must = the csa of the associated line conductor.

I wouldn't carry out any work whatsoever without first establishing that the correct equipotential bonding conductors are in place.(See REG 131.8) When completing an Electrical Installation Certificate, a Periodic Inspection Report or a minor works certificate, the csa size material and confirmation of continuity is required to be entered on the certificate/s. Recording this as a deviation and leaving it to the customer to do something about it is irresponsible. On a PIR this would be recorded as a code 1. If you carry out any work on an installation without equipotential bonding, should an electric shock or fire occur then you could find yourself liable as you were the last person who worked on the installation.

 

[Cirrus]

Our clients (mainly local auths) are happy for it to be done this way. ALL bonding is in place but some needs upgrading to 10mm and for that we are asked to place it down on the NIC forms as a deviation.

 

[saveloy]

Our clients (mainly local auths) are happy for it to be done this way. ALL bonding is in place but some needs upgrading to 10mm and for that we are asked to place it down on the NIC forms as a deviation.

Sorry I misunderstood your reply to the OP. I was trying to point out the importance of determining the provision of bonding before starting any other work. If it is not there in the first place, then there really is no point in continuing, as any work that is carried out will never comply to BS7671 due to the abscence of bonding.

 

[Cirrus]

Totally agree

 

[sparkyork]

hi, right then next week ill be going back to this job and will upgrade the main earth as well as the tails.

i appreciate what you say about main bonding and whole heartidly agree with it, as for the job that this post applies to i will be ringing the sparky firm up that fitted the new consumer unit and certificated it all and will see if i can get them to go and do it!! if not then i will do it next week.

however there are a few points to all this bonding and regs malarky that should be a little flexible, like the other job i went to this weekend was to simply drag some old wall light wires out of the wall back to JB's and disconnect, the board looked like it had mian bonding in place but an further investigation it didnt. and after some testing it turned out that the main earth was way over recommended limits and couldnt rcd test due to touch voltages.... so are you supposes to before starting work get your wander lead out and test the opossing ends of main bonding conductors before starting work?? i cant see this happening in all situations, half the time you have a look and trust its in place fully, as you lot know just cos its there dont mean its continuous..

so now the customer knows his installation is dangerous, i know its dangerous and next weekend im fitting a new board aswell as sorting all his bonding out, he was actually gonna do the work himself and would not of ended up doing any testing what so ever allowing the problems to continue..

in this installations case i would of had to of done a mini PIR to assertain the problems with everything, in my opinion this installation hasnt been left in anymore of a dangerous state than it was and next weekend itll be pucka, which it would not of been if he had of done the work himself.

i appologize for wittering on a bit but theres gotta be some give n take, i mean if someone just leaves something with blatent faults without doing anything at all then they diserve crusyfying but surely not in this case???

 

[saveloy]

hi, right then next week ill be going back to this job and will upgrade the main earth as well as the tails.

i appreciate what you say about main bonding and whole heartidly agree with it, as for the job that this post applies to i will be ringing the sparky firm up that fitted the new consumer unit and certificated it all and will see if i can get them to go and do it!! if not then i will do it next week.

however there are a few points to all this bonding and regs malarky that should be a little flexible, like the other job i went to this weekend was to simply drag some old wall light wires out of the wall back to JB's and disconnect, the board looked like it had mian bonding in place but an further investigation it didnt. and after some testing it turned out that the main earth was way over recommended limits and couldnt rcd test due to touch voltages.... so are you supposes to before starting work get your wander lead out and test the opossing ends of main bonding conductors before starting work?? i cant see this happening in all situations, half the time you have a look and trust its in place fully, as you lot know just cos its there dont mean its continuous..

so now the customer knows his installation is dangerous, i know its dangerous and next weekend im fitting a new board aswell as sorting all his bonding out, he was actually gonna do the work himself and would not of ended up doing any testing what so ever allowing the problems to continue..

in this installations case i would of had to of done a mini PIR to assertain the problems with everything, in my opinion this installation hasnt been left in anymore of a dangerous state than it was and next weekend itll be pucka, which it would not of been if he had of done the work himself.

i appologize for wittering on a bit but theres gotta be some give n take, i mean if someone just leaves something with blatent faults without doing anything at all then they diserve crusyfying but surely not in this case???

With regard to trusting existing work/installations my answer would be DO NOT under any circumstances. TRUST NO-ONE.On surveying any job my first action would be to inspect the main earth bonding and main protective bonding conductors. As I posted before any work you carry out cannot comply with BS7671 if the earth bonding is not in place. If you are just quoting for a job then I would advise the customer ( if is not clear that the bonding conductors are adequate) that this will require further investigation and may carry an extra cost implication. Sometimes it may be possible to carry out a quick continuity test to establish the continuity of conductors and also to prove to the customer that they do or do not require improvement.
Whatever the situation I would NEVER carry out work on an installation until I was entirely convinced that the Bonding conductors were adequate.
As you were the last person to work on the installation and as a competent person you are required to address any issues so as to ensure that your work complies with the relevant regulations.
You may be liable if something went wrong!! Is it worth the risk?

 

[sparkyork]

i do see what your saying but there must countless people out there that just have a quick look under the sink, quick look in the gas meter and then crack on with everything, the previous firms ive worked for were always about time on the job and would expect me to know in a matter of seconds what the bonding was like. they would not of expected me to get the wander lead out and check for continuity of these bonding conductors.

again im not disagreeing im just saying there's gotta be a little bit of give n take, the wall light installation is no unsafer now than what it was before, and come next weekend it will be 1000 times better, you cant tell what state stuff is in till you physically start testing it as i found with the earth rod, which doesnt comply with the 200 ohm limit and ive never tested Ze or Ra before doing some work (unless im just a crap sparky! lol)

i mean whats better: 1. guy does work himself, sorts it out, jobs a good n, no testing done, sorted or

2. spark goes in, disconnects wall lights, tests, finds lots of problems, customer says come back next week n sort it.

yes the bonding wasnt up to scratch, but neither was the main earth, the earth rod, and i suspect im gonna get some funny results when doing EIC nex weekend aswell.
but it will all be made good and to the 17th. where as it wouldnt if i hadnt of gone in

i know technically you shouldn do work till main equip bonds are ok, but in summary you cant always tell and often find there not up to scratch when they look like they are. i did explain to customer that if i found anything untoward i would have to put it right, which i did and i am doing next week

 

[saveloy]

i do see what your saying but there must countless people out there that just have a quick look under the sink, quick look in the gas meter and then crack on with everything, the previous firms ive worked for were always about time on the job and would expect me to know in a matter of seconds what the bonding was like.

Just because other people have a quick look it doesn't make it right or good practice.Set your own standards

they would not of expected me to get the wander lead out and check for continuity of these bonding conductors.

Why not? It's the simplest method of verifying continuity of bonding conductors.

again im not disagreeing im just saying there's gotta be a little bit of give n take, the wall light installation is no unsafer now than what it was before, and come next weekend it will be 1000 times better, you cant tell what state stuff is in till you physically start testing it as i found with the earth rod, which doesnt comply with the 200 ohm limit and ive never tested Ze or Ra before doing some work (unless im just a crap sparky! lol)

I am not being sarcastic when I state this but you will find no mention of give and take when it comes to electrical installation work. It may sound a bit an@l but by conducting a few simple inspections and or tests before you start work will highlight the difference between a professional electrician and a crap sparky.

i mean whats better: 1. guy does work himself, sorts it out, jobs a good n, no testing done, sorted or

2. spark goes in, disconnects wall lights, tests, finds lots of problems, customer says come back next week n sort it.

I think we both know the answer to this

yes the bonding wasnt up to scratch, but neither was the main earth, the earth rod, and i suspect im gonna get some funny results when doing EIC nex weekend aswell.
but it will all be made good and to the 17th. where as it wouldnt if i hadnt of gone in

If the main earth and rod are not up to scratch and you know it beforehand then you defintly should not start work before this is rectified.
If on the other these problems are identified during testing then I agree there was not a lot that could have been done prior to the work being undertaken

i know technically you shouldn do work till main equip bonds are ok,

So why are you then?

but in summary you cant always tell and often find there not up to scratch when they look like they are.

Yes you can. By visual inpection and/or a continuity test.

i did explain to customer that if i found anything untoward i would have to put it right, which i did and i am doing next week

This is the right approach and you are not leaving yourself open to further problems later on.

I realise that this post may come across as confrontational but it is not mean't to be.

All I was trying to do was offer advice as to how to avoid certain problems in the future and get your jobs to run more smoothly

My initial approach to any job is always the same.On initial survey of a job ie estimating I always inspect the bonding/ earthing. This way You can immeadiatly point out potential problems to customers. In doing this they are then prepared for extra work as required.You are also then better prepared to carry out the work. It also looks more professional.

We've all been there. Go round to a customer to change a light fitting,simple job blah blah blah. Then you go to fill out a minor works, oh poo no bonding. When you tell the customer there is a chance that they will think you are trying it on for a bit of extra work, after all everyone in the whole building trade is a ripp-off merchant

There are no grey areas in electrical work and as long as you follow regs and procedures to the letter you will not leave yourself open problems later on. Cover your --- at all times.You will also come across as more professional to customers which in turn should generate further work. All IMHO of course.

 

[sparkyork]

cheer savloy, just got in from work ! firstly theres not a lot of point in me responding much more to this, i know what the crack is with trade and cant afford to turn work down at the minute etc etc.

id like to know how many people test the main earth and do a continuity check on bonding when either estimating for work or before starting work. or whether they just confirm it on a visual, like i did, but turned out that they were both below standard on the test.

im not a crap sparky and do a good job, visual inspections are clearly just that, if ive seen something that looks ok then you only find out its not till you start testing.
again id like to know who gets there wander leads out to testing continuity of bonding conductors before starting work, if they look ok visually (as mine were on this job)

i honestly appreciate your comments and have taken several points on board, but i will maintain the above comments and also add that without doing a full pir on a job whilst estimating it you will never know the full extent of an installation..you may get your leads out and confirm cont of boinding conductors, and do a loop test on the mains, then after you do all this you fit a light fitting and find you got no cpc continuity, or other high r1+r2 related problem, these problems are always gonna occur unless im totally missing the whole point here, that the wierd and wonderful world of electrics!

im taking note of clarifying the main bonding and i may even confirm it with wander lead test from now on, but come on seriously who tests main Ze etc and bonding this way before doing works (other than visual)

i also dont mean to come accross confrontational im only 4-5 months in as been self employed and am still learning and will be learning for as long as im in this trade, like everyone else.

cheers


anyways im off for a well earnt shower now....