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Topic Title: 18 way 3ph board change
Topic Summary:
Created On: 11 January 2015 12:06 AM
Status: Read Only
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 18 way 3ph board change   - DOUGIE1000 - 11 January 2015 12:06 AM  
 18 way 3ph board change   - mantutu - 11 January 2015 12:22 AM  
 18 way 3ph board change   - DOUGIE1000 - 11 January 2015 12:57 AM  
 18 way 3ph board change   - Jaymack - 11 January 2015 04:29 AM  
 18 way 3ph board change   - leckie - 11 January 2015 08:40 AM  
 18 way 3ph board change   - OMS - 11 January 2015 10:05 AM  
 18 way 3ph board change   - dickllewellyn - 11 January 2015 10:22 AM  
 18 way 3ph board change   - hertzal123 - 11 January 2015 10:32 AM  
 18 way 3ph board change   - Manxie - 11 January 2015 10:59 AM  
 18 way 3ph board change   - DOUGIE1000 - 11 January 2015 02:05 PM  
 18 way 3ph board change   - dickllewellyn - 11 January 2015 02:16 PM  
 18 way 3ph board change   - DOUGIE1000 - 11 January 2015 11:05 PM  
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 11 January 2015 12:06 AM
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DOUGIE1000

Posts: 4243
Joined: 13 August 2005

Ok so on Tuesday I have a 18 way 3ph board to change for new.

Wired in top entry singles in 150mm tunking. Not one of the earth's or neutrals within the board match the mcb order.

What would you do. I'm looking at almost 50 single phase circuits.

I'm going to struggle to get the earth's and neutrals to match up. To make it worse as always very little is marked and no circuit charts or diagrams on site. Latest EICR states incorrect sequence of earth and neutral and also notes 50% unknown what is powering despite leaving off for a period of time.

What would you guys do in the neutral/earth. Almost all fittings are 2d fittings or LED retrofits.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 11 January 2015 12:22 AM
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mantutu

Posts: 123
Joined: 16 June 2013

I do not think I would struggle to match earth and neutrals to designated circuits. Then again I probably would test more than you think you are capable of, or have under priced your quotation.
 11 January 2015 12:57 AM
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DOUGIE1000

Posts: 4243
Joined: 13 August 2005

Hiya mantutu. Time is a factor. This is an active hotel. Unfortunately the board is kitchen and ground floor lights / sockets. We have a very short window to carry out works.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 11 January 2015 04:29 AM
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Jaymack

Posts: 5357
Joined: 07 April 2004

Originally posted by: DOUGIE1000
Ok so on Tuesday I have a 18 way 3ph board to change for new.

Optimistic in this Scottish weather with wind and snow!, but it's for lighting, so if you bed down in some of the numerous empty rooms with all of the equipment, go for it!

I'm going to struggle to get the earth's and neutrals to match up. To make it worse as always very little is marked and no circuit charts or diagrams on site. Latest EICR states incorrect sequence of earth and neutral and also notes 50% unknown what is powering despite leaving off for a period of time.

What would you guys do in the neutral/earth. Almost all fittings are 2d fittings or LED retrofits.

Test during daylight and well beforehand, take the appropriate precautions and remove the neutrals in unison to see unlitted fittings. The earths should presumably correspond to tests at groups of fittings, using the Live or the newly found Neutral as a link for continuity.

Regards
 11 January 2015 08:40 AM
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leckie

Posts: 4323
Joined: 21 November 2008

My approach would be firstly to cable mark all the line conductors and fill in a circuit schedule for the existing set up so cable 1 corresponds to circuit 1, existing overload device type and rating, etc.

Then I would get a clamp meter on each line conductors and try to find he corresponding neutral conductor, confirm it by removing the overload device, and mark the neutral cable. By doing this, most of the circuit should able to be established. Any remaining circuits will then require further investigation, but it's a start. Identifying the cpc's is going to be trickier. For example, if the existing containment is steel, there could be numerous parallel paths that make identifying all cpc's virtually impossible. Some may be fairly straightforward as Jaymack described. However, you are only changing the board. You will not be leaving the installation in a worse condition, and I presume you will be testing the circuit identified for Zs. You can only do what is possible under the restraints that the client puts on you. If you had to carry out a distress change to a board in a hospital You would probably not have time to test much at all; but the board would still require a change wouldn't it? So it depends on the situation in my opinion.
 11 January 2015 10:05 AM
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OMS

Posts: 22359
Joined: 23 March 2004

I'm going to struggle to get the earth's and neutrals to match up.


and the problem is.......... ?

They can be found if you put in enough time and effort - what benefit does it bring.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 11 January 2015 10:22 AM
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dickllewellyn

Posts: 1410
Joined: 19 March 2010

Can I ask what the purpose of the board change is? Will you be filling it up with RCBOs? Unfortunately if that's the case, you will need to find the neutrals. If not, can you change the board as it is putting individual conductors back roughly in the positions they were? You may find that some are immediately apparent where they should be, some will be very easy to test, and that will narrow it down for the others too.

I'm afraid the short answer is either put it back as it is, or spend the time and put it how you would like it.

-------------------------
Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 11 January 2015 10:32 AM
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hertzal123

Posts: 468
Joined: 26 August 2007

In addition to the clamp meter test,I would remove trunking lid if possible and check for taped groups of cables,since singles are usually installed in this way.
Regards,Hz
 11 January 2015 10:59 AM
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Manxie

Posts: 246
Joined: 08 January 2015

i presume you will be carrying out tests of the circuits.
Once the old board is stripped out, test all the cables.
This will then identify all the circuits prior to dressing into the new DB

Regards
Charlie
 11 January 2015 02:05 PM
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DOUGIE1000

Posts: 4243
Joined: 13 August 2005

Hiya. The board change us due to old dorman smith and hotel wanting to upgrade do to parts being difficult to obtain. There is several rcbo's however it's ring mains wired in t+e due to refurbished rooms many years ago. The lights are wired in conduit metal in singles.

I like the idea of clamp testing sounds good actually and don't know why I didn't think of that.

The board was tested in November by a 3rd contractor who I think wrote test sheet from the door. Only thing they picked up on was incorrect/missing circuit identification and also incorrect c32amp MCBs on lighting circuits.

A full EIC will be issued during upon compleation.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 11 January 2015 02:16 PM
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dickllewellyn

Posts: 1410
Joined: 19 March 2010

Good luck with it Dougie. I often find with jobs like this that the thought of it is worse than it actually is once you get stuck in. I think you will be able to figure it out in such a way as to get the board changed safely and identified circuits without too much interference. The last such job i did was a pair of old Crabtree c50 boards into a new memshield 3. What I found on that occasion was that by the time I'd stripped out some of the isolators and boxes in the plant room that were redundant, I could mount the new memshield 3 alongside the old boards in such a way as to figure bits out and move them over to the new board as I go. Once it was all swapped over the old boards were stripped out, holes in trunking etc filled, and all put back together. I'd been having nightmares in the run up to the job, but in the end I could do the majority of the work in office hours without too much disruption, then a Saturday when the offices were shut to move over the last few bits and finish off the testing still to do.

-------------------------
Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 11 January 2015 11:05 PM
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DOUGIE1000

Posts: 4243
Joined: 13 August 2005

Thanks for input guys. Again some good points. I was wanting to get the earth's and neutrals in correct order with the MCBs instead of just chucked in.

I don't like idea if just chucking naturals into the neutral bar. I will clamp the MCBs. As for the earth's well this will just have to be left long and maybe a return visit.

Many thanks for input again guys

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
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