Location of PME Links

[Plonker 3]

where abouts are these ryefield boards going to be located?

 

[maddog]

On the wall within the Residential riser cupboard

 

[Knobhead]

Sorry for the delay, been away for a bit.
The landlords DB's are also every 3 floors, for corridor lighting and sockets, stairway lighting and what have you. These are fed by busbar trunking, Tapped off every third floor. This is because the Landlord's power requirements is not so substantial. But to supply 400 flats off of busbar trunking (that's 400x100A fuses), is going to be very expensive. Space is tight in the risers, so forget about putting multiple busbar trunking, it takes up too much room.
At each Ryefield board, there will be a maximum of 30 flats being supplied. That's 10x3c25mm cables out of the header trunking, running up the riser to the floor above, 10x3c25mm cables out of the header trunking and out through a letterbox to feed this floor, and 10x3c25mm cables from the bottom of the ryefield board and down to the floor below.
Each header trunking is over 150mm2 and over a meter long. Each Ryefield board is about 600/700mm wide and about 1000mm in height.

Just done a search and Eaton's range only goes up to 6300A, shneiders to only 5000A.
So we are talking about 6 or 7 busbars to feed that lot. Just isn't the space for that.

You haven’t a clue what you’re talking about have you? What is your role in this project?

No one in their right mind would install a single riser. There’s no way am I going in to X linked risers on here.
One failure = total blackout = 400 unhappy tenants = landlord’s rep hanging by his ankles out of a top floor window.
Added to which, cables traversing three floors isn’t going to go down well with the fire authorities.

Just to add to your misery, have a look for the DNO’s diversity figures for residential dwellings. (A hint, you’ll not find it in the OSG or BGB)

Stick to wiring the corridor lights off the landlord’s boards and making the tea for the guys that do know what they’re doing.

 

[maddog]

Tony.
Not only are you a grumpy git, as you state in your profile. But what you failed to mention is the fact that your head is stuck so far up your own arse that you cant even read.
You repeatedly get it all wrong. Even in this thread, no matter how clear it is made, you keep getting it wrong and another member who was reading the very same posts has had to clear it up for you. And by the way, was far more help than you in just one of his posts than you ever have been. I got a reply from you on a previous post and you got it all wrong that time too. Fortunately, there are some helpful sparks on here that can actually read.
Read the posts man.
I didn't design this. I am an electrical installer who is working by the drawings.
As stated, there is a landlords riser and a residential riser. Many other risers too.
But only one riser that feeds the flats.
Yes, this is allowed. I know this because Ive seen it many times before. I don't know where you get the idea that cables going though 3 floors is wrong. The only cable that traverses 3 floors is the supply cable. Which by the way, comes all the way from the basement (a bit more than 3 floors).
The SWA from the ryefields to the meters goes a maximum of 1 floor, either up or down.
All risers are fire protected.
Please, keep your divine wisdom for yourself and your family. Because all it is doing here is going to waste.

 

[Knobhead]

Sorry for the delay, been away for a bit.
The landlords DB's are also every 3 floors, for corridor lighting and sockets, stairway lighting and what have you. These are fed by busbar trunking, Tapped off every third floor. This is because the Landlord's power requirements is not so substantial. But to supply 400 flats off of busbar trunking (that's 400x100A fuses), is going to be very expensive. Space is tight in the risers, so forget about putting multiple busbar trunking, it takes up too much room.
At each Ryefield board, there will be a maximum of 30 flats being supplied. That's 10x3c25mm cables out of the header trunking, running up the riser to the floor above, 10x3c25mm cables out of the header trunking and out through a letterbox to feed this floor, and 10x3c25mm cables from the bottom of the ryefield board and down to the floor below.
Each header trunking is over 150mm2 and over a meter long. Each Ryefield board is about 600/700mm wide and about 1000mm in height.

Just done a search and Eaton's range only goes up to 6300A, shneiders to only 5000A.
So we are talking about 6 or 7 busbars to feed that lot. Just isn't the space for that.

YOU read YOUR posts #1 #4 #7 and then tell me what I’ve misunderstood. All we can do is go on the information provided.

Not until #14 do you say there’s multiple risers. Then #15 you comment on the size of the riser.

I can assure you the loading does not = 400x100A which is why I said to look for the DNO’s diversity figures.

 

[maddog]

You was corrected before by another reader. I cant be bothered now.
Again you are missing the point. "400x100A fuses" was not a calculation.
Just stating that It was a lot of flats to feed. Along with not specifying what the trunking's maximum load was, or by stating "6 or 7".
I wasn't being specific, because it didn't matter. There just isn't enough room.
You are just a sad little man trolling this otherwise good website.
Just looked through all your posts of today.
What a complete **** you are.

 

[Engineer54]

I'm still a little confused on a few things, the main worry being as to how these 3 X 30 way Ryefields are being connected to the 185mm 4 core cables?? Surely they aren't being in and out connected off the Ryefield bus bars, because if they are, unless i'm missing something at least two of those 3 Ryefield panel bus bars are going to be potentially over loaded!! They will be carrying the load (which they were not designed or sized for), from the other Ryefield panels, as well as it's own supplied load....

 

[shanky887614]

I'm still a little confused on a few things, the main worry being as to how these 3 X 30 way Ryefields are being connected to the 185mm 4 core cables?? Surely they aren't being in and out connected off the Ryefield bus bars, because if they are, unless i'm missing something at least two of those 3 Ryefield panel bus bars are going to be potentially over loaded!! They will be carrying the load (which they were not designed or sized for), from the other Ryefield panels, as well as it's own supplied load....

nothing to be confused about he is "mad dog murdoch"

 

[Knobhead]

I'm still a little confused on a few things, the main worry being as to how these 3 X 30 way Ryefields are being connected to the 185mm 4 core cables?? Surely they aren't being in and out connected off the Ryefield bus bars, because if they are, unless i'm missing something at least two of those 3 Ryefield panel bus bars are going to be potentially over loaded!! They will be carrying the load (which they were not designed or sized for), from the other Ryefield panels, as well as it's own supplied load....

I’ve given up, every time the OP appears the game play changes. Nothing has stayed constant in his posts. The supply to 400 flats is now the landlord service supply. Only a slight difference.

The bottom line is he’s a cable monkey that’s seen something he doesn’t understand.



If you allow 3.5KW* per flat even with +25% as contingency = 1750KVA = 2333A @433V 3Φ.
Using multiple risers with switched cross connections and sectioned risers they get to be of a reasonable size.
It’s no different to a local area system except it goes upwards and not outwards.



*I’ve got the actual figure somewhere on this black hole that pretends to be my computer. If you go in to the allowance the national grid makes per household you’ll laugh, it’s a paltry amount.



For the OP’s information, the title “grumpy git” isn’t in my profile at all. It came about as a joke between some of the moderators and myself a while ago, it stuck and I’m quite happy with it.

 

[maddog]

Engineer54 that is a good point and something I never thought of. The Ryefields in the residential riser cupboards (which is separate from the landlords riser cupboards) do indeed have an in and out connected to the Ryefields busbars. Something I never thought about, but as I said, I'm normally a flat rat and all this is quite new to me. Which is why I'm here talking to you about it.
So just to be clear, is what you are suggesting SWA cables running up the residential riser to a feed unit on the busbar trunking at intervals, depending on the load, covering the number of floors it can handle and tapped off at each floor to a 10 way Ryefield?
No information has changed. You are just getting more information as the thread goes on. The landlords riser has nothing to do with the residential riser. It is 20m away. Only mentioned the landlords riser because it is supplied how you suggested the residential riser should be

 

[Engineer54]

I think you need to post up a photo or two of one of these Ryefield panels that has been connected to one of these 185mm SWA cables, otherwise it's all just assumptions being made on my part...

 

[maddog]

If it wasn't the xmas hollidays you'd have them already. Not back for another week but I'll post them as soon as I can.

 

[Engineer54]

If it wasn't the xmas hollidays you'd have them already. Not back for another week but I'll post them as soon as I can.

I look forward to seeing those photo's. As they say a photo or two can save a thousand words!! As well as a lot of misunderstanding lol!!

 

[Knobhead]

There’s two scenarios, either the boards are (A) tapped off the 185 or (B) the 185’s go via the boards.
(B) Would be very dodgy if the busbars aren’t up to it.
There’s a third option which I’d go for but it would involve a 2[SUP]nd[/SUP] cable and removable links. I’ll do a drawing later, I’m off out for a farewell drink with my son soon.