I would appreciate your input lads

[wade88]

Alright lads,

Can anyone see a problem with this. Excuse the drawing, im fairly rubbish at clearly drawing things and have most definitely to all you technical chaps out there, murdered the drawing to bits, but im just trying to get scope around the general idea. Which i think is clear enough.

4 core SWA will be travelling across two warehouses to be terminated into new TP+N board. Planning on taking the existing incoming supply and splitting it down via service blocks to be able to accommodate the existing boards (of minimal load) and the new board. Industrial work such as this is not my usual forte, however it is becoming more of what i do now, i feel competent to do the work, would just appreciate a nudge in the right direction should i need it.

Tin hat is on, if you need to be brutal here, by all means go ahead. i want a safe and future proof install so if i need a good kicking to achieve that then im ready for it. I'll do my very best to answer your questions as accurately as possible.

Cheers guys,

 

[Spoon]

Soz Wad, I take it that DB1 & DB2 existing and you are adding DB3?
Is it the schematic diagram you would like commends on or the install method?

 

[Darkwood]

You would require an isolator upstream (supply end)of the swa to DB3 also i assume you missed the N out on DB2 by accident

 

[wade88]

Yes missed the neutral by accident, also forgot to add isolator for DB3, both are present. What i was concerned about really, was just the splitting of the power at service blocks, and phase balancing really.

 

[JD6400]

I think you have not got any form of discrimination in there for the new sub supply ?

 

[Darkwood]

Ideally if designed from scratch the service blocks would be replaced by a busbar chamber with an isolator for each out going supply i cant comment regarding loading as you supplied no info regarding existing loading per phase and proposed new DB3 loading.... using the service blocks is ok as long as the service blocks are not been pushed past their design in no' of cables tapped off or loading of the system overating the blocks, but if possible a busbar would allow for expansion while affording a proffesional look.

 

[wade88]

Well i am putting the service blocks into an enclosure to keep it looking tidy and primarily had considered the bus bar option, but just went for the blocks to keep costs a little lower.

I know guys sorry i havent gone to the lengths so far to provide with more details, my query initially was just in the basic lay out and design. I was just wondering if any immediate alarm bells would ring. The load on DB3 is going to be substantial and will be the primary consumer. DB1 feeds the high bay lighting, DB2 the office above, which is only occupied by two people (minimal draw - usual suspects, 2 pc's, copier, couple of fluros).

Im working late tonight to make a start on the getting the cable basket up not looking forward to it at all.

 

[44ALLAN]

Don't know about anyone else but I always buy SWA with an extra core for a dedicated earth.
Agree with the busbar section too...........far neater IMO.

 

[drew35]

Is that a separate neutral isolator after the meter or a service block? Shouldn't there be a four pole isolator, and not a three for the line conductors only.

(Sorry to hate on the drawing, I use a pritt stick for circles and a 9v battery for rectangles when I do my drawings. They must be sitting on my office desk for a reason?)

 

[Darkwood]

I would spec up the load characteristics of DB1 as you seem to have high bay lighting on 1ph if i read correctly .... you would be supprised at just how much load this may take and its possible you have a heavy loaded phase that will create all sorts of issues if your adding a heavy loaded 3ph board as well.... worse case would be a need to balance the high bay lighting over three phases to give the capacity you may need, also look into heating loads which may not be apparent at the moment while they are off.

 

[telectrix]

if DB1 and DB2 are adjacent, could you not replace both with a 3phase board (with sigle phase outputs) so as to balance the phases better? oh, and the isolator from the meter should be 4 pole IMO.

 

[Knobhead]

Ben, take on board what’s been said about fused switches and the loading for the lighting board. Come back with a new proposal including the length and loading of the separate runs.

 

[wade88]

Thanks lads,

you are all gems

 

[wade88]

Can someone point me in the direction of a 100amp 4 pole isolator that isnt a rotary then. having trouble digging one up

 

[Spoon]

If you are doing to re-draw the schematic I would put location boxes round the equipment (usually done as dotted or phantom lines). I take it that the existing incoming supply and DB's are in one warehouse (unit 11)? I'd also ident the cable going to DB3, as you mentioned, this is going through 2 warehouses before getting to the new DB.

 

[Bobster]

Is it to fit in a db? Or a stand alone unit?

 

[wade88]

View attachment unit 11 boards.pdf
Make more sense?

 

[wade88]

Excuse the rough drawing again, just for illustrative purposes. N currently runs to a service block, and N's taken from it. A 4 pole isolator would definitely be best for this arrangement then and then taken from isolator to seperate block to be split?

 

[Bobster]

So your looking for something similar to the mem switch fitted for db2?

I' recommend the ones we use on site but I think it might be a bit overkill for the purpose your wanting it for?

something like this? http://srselectrical.co.uk/index.php?route=product/product&product_id=567

 

[Bobster]

Sorry realise the link I've just posted is only 3pole.

This is the company we use for isolators, I'm guessing it'll probably be out of your price range

http://www.craigandderricott.co.uk/

 

[vaughant]

General drawing looks ok,can't say I've seen many 4 pole DB's in my 17 years of industrial work,nearly always 3 phase but with the neutral and earth into a block internally so I wouldn't be too concerned overall if that's all that's available.Fitting 4 core swa is always a good move IMO as it keeps the earth arrangements neater and safer.How crap is that db1 in the existing photo?just two meter tails stuffed in from conduit!!!!If you need an example of how you generally view power distribution in schematics I'll try and post it up on here,although I like your overview and would certainly add that as well,for sparks like me who generally deal in schematics it's nice to have the more traditional line drawings as well.

 

[Bobster]

Vaughant, didn't notice that on my first view.

Wade, do the line and neutral tails go through separate holes in the top of the db?

 

[wade88]

Vaughant, didn't notice that on my first view.

Wade, do the line and neutral tails go through separate holes in the top of the db?

They do indeed my friend

 

[wade88]

Nice and neat.

 

[44ALLAN]

Wade
The space above the meter looks mighty cramped for what you intend doing.
Is there no space further along where you could mount another board?
Lots of cable and glands etc in that small space ain't going to look right mate IMO

 

[wade88]

Wade
The space above the meter looks mighty cramped for what you intend doing.
Is there no space further along where you could mount another board?
Lots of cable and glands etc in that small space ain't going to look right mate IMO

Absolutely Allan, that is why i have gone and re-measured, and will be moving the MEM isolator to the right of the wooden mounting board, and placing my new box in its place next to the psace heater switch. Should be plenty of space there dont you think? The SWA i have already managed to drag across the units (that was some seriously hard work!) and have decided to abandon cable basket as it was a total nightmare considering the racking lay outs etc, and have gone for the cleat and girder clip option instead. Cable is already cleated on the vertical and now will be terminated just to left of that existing 2inch galv trunking. I think there should be plenty of space there and as you will say will free it all up a bit and stop any over crowding.

 

[wade88]

Vaughant, didn't notice that on my first view.

Wade, do the line and neutral tails go through separate holes in the top of the db?

You have me all concerned with eddy currents now. I was planning on putting each phase and the N into the Adaptable box via seperate glands, and then the outgoing phases out through their own sperate glands, would have looked neat, but i dont want to cook anything! Does anyone think Eddy currents could pose a significant problem here? Am i best to cut a ovular slot in the box and just put all cables through together?

 

[Knobhead]

You still can put them through seperate slots, just cut a slot between the holes. Don't use steel lock nuts :wink5: (I've seen it done, knocked out a 1000KVA transformer when the LV box went up in flames).

View attachment 14982

 

[JD6400]

You still can put them through seperate slots, just cut a slot between the holes. Don't use steel lock nuts :wink5: (I've seen it done, knocked out a 1000KVA transformer when the LV box went up in flames).



View attachment 14982

Just be careful of the ip rating if you do go down this route .

 

[Silly Sausage]

What's the minimum width that the slot can be?

 

[JD6400]

Going to embarrass me self now as this is from memory but is it 1mm if on the top ?

Edit ; To be honest i wont accept any holes / gaps on a new install .

 

[Silly Sausage]

IP4X, <1mm

Would you use an insulated gland plate then?

 

[wade88]

Well ill be terminating from the bottom, and did my homework on eddy currents earlier and noticed the cutting slot between hole method mentioned so i think i will do it this way. Thanks fellas.

Tell you what though, i am DONE dragging that SWA around till ive had some lunch. Total calories burnt lugging that stuff around, 7689, need to get myself to greggs to get some good high fat calories back in me. Steak slice here we come.

 

[Chr!s]

Ipxxd 1mm 100mm long

 

[Knobhead]

Just be careful of the ip rating if you do go down this route .

I filled the slots with epoxy resin.
Width to equal plate thickness.

View attachment 14990

 

[Deservices]

I would check the current that your bay lighting is pulling, as its going to make a big difference and might take 1 phase over the edge.is it 200 or 100 anp main inc fuses? Might be best to put a small 3 phase board there especially if you going to be loading the new board with 3 phase motors and maxing its load. What size swa you putting in?

 

[vaughant]

This I felt looked poor,I'd have mounted the db closer to the trunking or trunked it in.Although with the amount of effort your putting in wade88 I reckon this will look great when finished.Not meaning to teach you to suck eggs but remember to do as much labelling as you can,it helps no end when you need to isolate or fault find.

 

[Engineer54]

We always use insulating boards entering/exiting metal switchboards and the like, for our single core distribution cables, which can sometimes be in multiples of cables per phase... Haven't slotted gland plates for donkey's years now, but it is a suitable and viable solution where your working on existing board/panel...

 

[johnboy6083]

I've used both Paxolin and PVC sheet for glanding single core cables. It's a neat solution.

 

[Knobhead]

Both unacceptable under M&Q. We had to use metal.