Using Type D MCB for discrimination

Leesparkykent · Jan 2, 2018

ipf said:
I think we've been here before

Think the OP is trying to reinvent the wheel though

. I can understand where the OP is coming from as he might be competing against idiots that wouldn't know what discrimination is...Let alone how to design discrimination into the installation. If its detailed properly in a quote then it shouldn't be a problem...Unless the customer just wants the cheapest quote and couldn't give a hoot about the standard/functionality of the installation...Then if I was him I'd say good riddance.

Michaelwgroves · Jan 2, 2018

Leesparkykent said:
Think the OP is trying to reinvent the wheel though . I can understand where the OP is coming from as he might be competing against idiots that wouldn't know what discrimination is...Let alone how to design discrimination into the installation. If its detailed properly in a quote then it shouldn't be a problem...Unless the customer just wants the cheapest quote and couldn't give a hoot about the standard/functionality of the installation...Then if I was him I'd say good riddance.

I think you are spot on,

This installation seems to fit between commercial and domestic, both industries are served well, but there is nothing in this middle ground. Lots of commercial distribution options, but in this case it’s now obvious none of the manufacturers have designed a SP board for BS88 fuses.

I challenged the wheel, come come full circle. Cheers guys.

buzzlightyear · Jan 2, 2018

[ElectriciansForums.net] Using Type D MCB for discrimination

if is was me this what I would put in for sub mains for HMO for 5 floor job .

Cadgey123 · Jan 2, 2018

Leesparkykent said:
I agree with the OP though that on a new install, service terminal blocks (or Henley/Isco blocks that you love them being called) look like shyt. If I could hide them in the trunking then might consider it but if not I'd rather weigh out on a busbar chamber. Could pick up a 100A one up for about £180...in the grand scheme of things I don't think it's that much when rewiring a big HMO.

I agree with LSK

With what I have heard in regards to the design of this job already, you have to spend some sort of money on a decent well structured submains system.

Get a Ryefield and do it properly IMO.

Would hate to see cables flapping about connected into Henley’s.

ipf · Jan 2, 2018

Michaelwgroves said:
I think you are spot on,

This installation seems to fit between commercial and domestic, both industries are served well, but there is nothing in this middle ground. Lots of commercial distribution options, but in this case it’s now obvious none of the manufacturers have designed a SP board for BS88 fuses.

I challenged the wheel, come come full circle. Cheers guys.

Never mind a single phase bs88 board......I recently had a 'qualified' bloke telling me that bs88 3 phase were no longer satisfactory.....'you've got to have a TP breaker because if a fuse goes you won't isolate all phases'......plonker!

ipf · Jan 2, 2018

Cadgey123 said:
I agree with LSK

With what I have heard in regards to the design of this job already, you have to spend some sort of money on a decent well structured submains system.

Get a Ryefield and do it properly IMO.

Would hate to see cables flapping about connected into Henley’s.

In this case that's probably going a bit too far, cost wise especially. Small bb chamber and sw/fuses, as Lee says.
General way for a small block of flats.

Wilko · Jan 3, 2018

Hi MWG - I feel your pain and don't mean to add more, but iirc the supply is 100A and it's split 5 ways, so is 5 distribution circuits with 63A ocpd right? Perhaps the rooms can run on the 32A fuse arrangement or does the supply need looking at? Apologies if you've already covered this or if I've misunderstood

buzzlightyear · Jan 3, 2018

Wilko said:
Hi MWG - I feel your pain and don't mean to add more, but iirc the supply is 100A and it's split 5 ways, so is 5 distribution circuits with 63A ocpd right? Perhaps the rooms can run on the 32A fuse arrangement or does the supply need looking at? Apologies if you've already covered this or if I've misunderstood

63A sub mains board off a 32A MCB? - MyBuilder - https://www.mybuilder.com/questions/v/6030/63a-sub-mains-board-off-a-32a-mcb mmm.

Michaelwgroves · Jan 7, 2018

U-Turn in progress..............
Having discounted the Ryfield board early on mainly because of cost I've come full circle. I've looked at every option, in reality 5 no. switched fuses with a quality distribution board is a similar cost to Ryfield.

Therefore design is Cut-out > Isolator > Ryfield > CU on each floor.

Seems obvious now, but needed to kick it around before I could get my head around it.

Thanks for prompts gents,

wsoppitt · Jan 7, 2018

buzzlightyear said:
63A sub mains board off a 32A MCB? - MyBuilder - https://www.mybuilder.com/questions/v/6030/63a-sub-mains-board-off-a-32a-mcb mmm.

Buzz
Wouldn't include link to" my builder " question board as that 1st response is not particularly accurate in this case , I wouldn't listen to his advice.

buzzlightyear · Jan 7, 2018

wsoppitt said:
Buzz
Wouldn't include link to" my builder " question board as that 1st response is not particularly accurate in this case , I wouldn't listen to his advice.

what .

Using Type D MCB for discrimination

Leesparkykent

Michaelwgroves

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buzzlightyear

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Cadgey123

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ipf

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ipf

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Wilko

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buzzlightyear

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Michaelwgroves

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wsoppitt

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buzzlightyear

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