Just trying to get my head around this. My place of work had a new CU installed a few months ago. This was installed by a local NICEIC registered company. This is the picture of the previous installation, I assume its taking 3 of the phases, to power each individual board with a separate board. Old Installation New installation The mains switch is a three pole switch dis-connector (125A 3 pole) L1 -L2 -L3 all linked so is in effect a single phase board. My question is why the Neutral wire does not go into the switch, so if the main switch is switched off, the neutral will still be present? Should a 4 pole switch have been fitted or better an A type commercial board?
Well fitting a single phase board system, probably a stacked type would have been my option, The problem with doing it this way is it can be easily overloaded with so many spare ways and your not switching the neutral (which may not be needed in this instance, as you can undo the neutral link form the board) but a 4 pole switch could have been fitted if needed. Im not sure there is anything specifically wrong with linking out the switch as it is in effect a large single phase board now.
**** way to turn a three phase board into a single phase one should of used a proper linking kit not loops of cable
The SWA used is 3 core 25mm. This was the main switch that supplied the original 3 separate boards. The original SWA wire was 4 core. This main switch 100A, was fitted after and supplies the 3 phase board, notice the 25mm tails. don't know why they wired it single phase?
Seems a bit wierd to do it this way. They have 3 phases, they could have run 3 phases to the 3 phase board, and then used it to supply single phase circuits across the 3 phases. Now they have only one phase loaded, and have reduced the maximum load available load.
think someone *****d up then... I'd guess they ordered 3 core swa for a 3 phase board but someone forgot about the neutral.... depending on what the quote / estimate said you may have some come back for them to replace the cable for a 4 core, especially as now you wont be able to install any 3 phase equipment onto that board.
I'll talk to the facilities manager next week and see if I can dig out the quote. Regarding overload, I don't think they would be able to add any further circuits, so they could have opted for a smaller board instead of the current one. Also should they have given a legend providing the details for each circuit. i.e. no of points served and cable sizes etc?
Well the circuits appear labelled that will suffice, however you could always photo copy the installation certificate, in whole or just the circuit details, and put a copy in the board as it will have more specific details as you describe
I can't see from the picture but having a label on the front stating "Single phase supply only" or similar would have been a good idea in-case some one thinks its a 3 phase board
Something else that should be considered, is whether there is a 3 phase meter? Is a 3 phase meter more expensive than a single phase meter?
Just had a look at the Eaton broucher. At present they have a 125A TP (triple pole) configuration The electrician could have opted for a: Switch disconnector kit SPSN (including single phasing link) As Stu1312 said.
This is the labeling at present, notice the one 16A MCB been labelled 'UNKNOWN'. Can't show the front due to name of co., but it has 3 labels: 1) Name of co. 2) Label to identify two colour cabling used. 3) Label stating that the installation should be inspected in 5 years time.
You can get a single phasing kit for that board which shorts the busbars together at the top, and provides a DP switch at the bottom. That's what should of been used.
This is the old and now redundant 3 pole switch fuse. Where is my screwdiver? Found these tools left in the trunking. 2 x lines taped up, not sure if they are live? this looks like the electric meter as its labelled DB1. 3 phase - 4 wire.
So they have completely butchered a 3 phase supply and turned it into single phase?? that makes no sense what so ever.... one thing to check on if thats the case, is how you are charged for the 3 phase supply. Im not sure on specifics of 3 phase charges but i know a customer of mine had loading checked across phases because they were charged a rate for the highest current draw on a phase.. Something to do with keeping the suppliers phases balanced as well so they charged you if you drew a lot on any single phase... Not sure the same applies in your situation but in any case you could have gone from 90A across 3 phase to 90A on a single phase..
These are the remaining 2 phases which are energised. My book says the use of electrical insulating tape as the sole means of enclosure for termination is not acceptable. What should have been done? I would have removed them from the system so risk of shock is removed.