Using Type D MCB for discrimination

[Michaelwgroves]

Well you've understood wrong then. There is no regulation stating door must be top hung and whoever told you such is talking out their arse.

The door must be self closing, that's the important bit.

 

[davesparks]

Door needs to remain closed when not in use so needs to be top hung. A lock is not sufficient apparently! Had this conversation with Hager today.
Seems crazy to me, but they are the regs as I understand them.

Well it constantly in use as the electricity will always be flowing through it whilst the installation is live!
Show me where in the regulations it says it must be top hung? And if that’s the case then what about the ‘amd3 cu’s’ that don’t have a self closing lid??

If it’s that much of an issue to you then get a busbar and switchfuse setup, square d do a modular busbar chamber with space for 6 switchfuses which come with pre-manufactured connecting links.

 

[Ian1981]

The door must be self closing, that's the important bit.

You better tell Schneider that their eazy 9 consumer units don’t comply then.

 

[davesparks]

The door must be self closing, that's the important bit.

So mount the excel board sideways!

 

[Leesparkykent]

The door must be self closing, that's the important bit.

Explain this then? BG consumer unit.

 

[Rocboni]

Much better solution, I like it.

You said this was overkill on another thread. It is the best solution, and a "no brainer"

 

[Michaelwgroves]

I think the evidence is overwhelming, I agree what I was told today must be incorrect........

 

[Ian1981]

I think the evidence is overwhelming, I agree what I was told today must be incorrect........

Have a look on YouTube for hagers amendment 3 myth breakers regarding metal consumer units.
Whether the lid debate is on there , I can’t remember but worth a watch anyway.

 

[Octopus]

I think the evidence is overwhelming, I agree what I was told today must be incorrect........

But there will be muppets going around saying its the "law"

 

[Michaelwgroves]

You said this was overkill on another thread. It is the best solution, and a "no brainer"

I can't find that statement, but I have no problem doing a public U-turn when evidence proves my previous thoughts were wrong.

 

[buzzlightyear]

AD3 says about contentment of fire .not which way the front door flap is up or down or side to side.
just think the mcbs are made of plastic .

 

[westward10]

I agree that some type of fuse arrangement is the best option but is the supply not single phase? I have never seen an SP&N busbar chamber.

 

[Leesparkykent]

I agree that some type of fuse arrangement is the best option but is the supply not single phase? I have never seen an SP&N busbar chamber.

No props using a TPN one though.

 

[westward10]

No props using a TPN one though.

I agree but it is a big out lay when a main switch and service terminal blocks through to switch-fuses will serve the purpose.

 

[DPG]

AD3 says about contentment of fire .not which way the front door flap is up or down or side to side.
just think the mcbs are made of plastic .

That's why the access door is metal though.

 

[Rocboni]

I agree but it is a big out lay when a main switch and service terminal blocks through to switch-fuses will serve the purpose.

This was my thoughts, dual 6 way block, trunking and switch fuses to DP isolator £300 busbar chamber will double that.

 

[Leesparkykent]

I agree but it is a big out lay when a main switch and service terminal blocks through to switch-fuses will serve the purpose.

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.

 

[Michaelwgroves]

I agree that some type of fuse arrangement is the best option but is the supply not single phase? I have never seen an SP&N busbar chamber.

5 Way 125A SP+N Metalclad Distribution Board with Incomer | CEF - http://www.cef.co.uk/catalogue/products/1400074-5-way-125a-sp-n-switch-disconnector-metalclad-consumer-unit

 

[westward10]

5 Way 125A SP+N Metalclad Distribution Board with Incomer | CEF - http://www.cef.co.uk/catalogue/products/1400074-5-way-125a-sp-n-switch-disconnector-metalclad-consumer-unit

Good luck getting five 16.0 or 25.0 swa cables into that.

 

[ipf]

Bus bar chamber and switch fuses...it's fit for purpose and designed for the job. Out of meter into a 100A switch disconnector, into bus bar chamber, length of trunking slotted sat on top with paxolin between, bush switch fuses on to trunking, link bus bar chamber and switch fuses with singles in the trunking, gland SWA's into the switch fuses...Job done.

I think we've been here before

 

[Leesparkykent]

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]

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]

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

 

[Cadgey123]

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]

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]

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]

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]

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]

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]

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]

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 .