EIC for submain db rewire

[conrad]

My question wasnt about the correct way to install etc im aware of all points people have mentioned... More on how far would people go ensuring everything inline was adequate simply to provide just a quote and what tests would you carry out as could be very time consuming in this circumstance. Also on what details you would input on EIC as some have said they would only check submain woring on and mains. As we know alot would install without a thought. Explainig to clients isnt simple either, especially if it creates more work as "its been like that for years"will be their reaction...but taking into account all the points being made on adequacy of current installation etc would you just refuse to do anything unless all points are met. Thanks for replies peeps. In terms of discrimination it is as follows. I shouldve been more clear with details at start apologies...
Cutout
3phase 100A bs1361 feeds
DBmain (8 way)
3P MCB 60Amp 16mm4c (swa cpc) feeds
DB1 - 3Phase (8 way)
3P MCB 63A dont know cable size feeds
DB2 which has a 100A RCCB 30mA main switch and is 3 phase.
32 A single phase mcb (attached image) 6mm 3 c swa feeds
DB 3 which has 100A RCCB 30mA main switch single phase 5 way DB.. Think thats pretty accurate but is from memory as details are in the van which is outside and its cold .

 

[Toneyz]

My question wasnt about the correct way to install etc im aware of all points people have mentioned... More on how far would people go ensuring everything inline was adequate simply to provide just a quote and what tests would you carry out as could be very time consuming in this circumstance. Also on what details you would input on EIC as some have said they would only check submain woring on and mains. As we know alot would install without a thought. Explainig to clients isnt simple either, especially if it creates more work as "its been like that for years"will be their reaction...but taking into account all the points being made on adequacy of current installation etc would you just refuse to do anything unless all points are met. Thanks for replies peeps. In terms of discrimination it is as follows. I shouldve been more clear with details at start apologies...
Cutout
3phase 100A bs1361 feeds
DBmain (8 way)
3P MCB 60Amp 16mm4c (swa cpc) feeds
DB1 - 3Phase (8 way)
3P MCB 63A dont know cable size feeds
DB2 which has a 100A RCCB 30mA main switch and is 3 phase.
32 A single phase mcb (attached image) 6mm 3 c swa feeds
DB 3 which has 100A RCCB 30mA main switch single phase 5 way DB.. Think thats pretty accurate but is from memory as details are in the van which is outside and its cold .

That is very poor discrimination between RCD's if something with a earth fault is plugged in on DB3 this could trip out DB2.

 

[Richard Burns]

So the situation changes again.
You have no discrimination between boards and you now have no discrimination between RCDs as well.
So a short circuit at DB3 could readily take out DB 2 as well.
An earth fault DB3 will also take out DB2.
However this is not what you are installing. Though you would need to check the RCD is working which will be a nightmare of overlap.
Since you are doing a rewire of a whole area, I would say that you should also attempt to find out the supply cable size between DB1 and DB2.
Then you will be able to enter the circuit description details of the submains on the EIC, Zdb only being relevant at DB3.
Full circuit details and tests would be needed for the circuits you are rewiring from DB3.

 

[conrad]

That is very poor discrimination between RCD's if something with a earth fault is plugged in on DB3 this could trip out DB2.

Client says it occasionally trips at DB2 but it only feeds a couple of sockets and a light within the outbuilding the db is located in( which isnt occupied) and a greenhouse db so isnt a major inconvenience..

 

[conrad]

So the situation changes again.
You have no discrimination between boards and you now have no discrimination between RCDs as well.
So a short circuit at DB3 could readily take out DB 2 as well.
An earth fault DB3 will also take out DB2.
However this is not what you are installing. Though you would need to check the RCD is working which will be a nightmare of overlap.
Since you are doing a rewire of a whole area, I would say that you should also attempt to find out the supply cable size between DB1 and DB2.
Then you will be able to enter the circuit description details of the submains on the EIC, Zdb only being relevant at DB3.
Full circuit details and tests would be needed for the circuits you are rewiring from DB3.
View attachment 41417

Also the 63A @ db1 after the 60@ dbmain

 

[conrad]

Into DBmain from metering. Poor installation all round really. Main earth looks to be 10mm to met then 25mm into dbmain. Cant see incomer as 2 obsolete cables are cut sticking out covering it.

 

[davesparks]

That looks a lot like one of the tails entering through a separate hole in the steel enclosure, so you’ve got another non-compliance.

 

[Toneyz]

That looks a lot like one of the tails entering through a separate hole in the steel enclosure, so you’ve got another non-compliance.

That's it Dave kick him when he's down, these non-compliances are acuminating.And there is abrasive edge (no bush/Gromit to cable entry on left.

 

[conrad]

Observed, thats why i took the pic. Its Neutral and Earth. Also no lid for the trunking header which creates an Ip4x issue in top of db. I think these old brown tails are single insulated? Again where would you go with these. Observations on existing installation could be alot of work alone. These would hopefully have all been highlighted in the latest eicr.

 

[Toneyz]

Comments on existing installation.

 

[Ian1981]

Non compliance’s which do not result in danger or potential danger can be left and a comment made on the EIC.
It would be down to the installer to decide what constitutes a danger to the existing installation such as any possible eddy current issues which have been identified.
Look for any thermal damage to the surrounding enclosure etc.
If it can be rectified then do so.

 

[conrad]

So for this steel structure greenhouse am i correct that tnc cannot be used. The installation is obviously tncs.

 

[conrad]

So for this steel structure greenhouse am i correct that tnc cannot be used. The installation is obviously tncs.