DB installed connected & tested

[cliffed]

Just your thoughts on this DB,it’s a Lewden type,I personally don’t like them.
Bus bar,not ideal,main switch on right,space very tight to make connections,hate the rcbo’s,screws in front of each other,making it hard to retighten .

 

[telectrix]

you call that tight? wait till you try a schneider easy9.

 

[Leesparkykent]

I don't mind them for the money...my preference is hager but the lewden boards are my go to if there's a budget.

If there wasn't so much slack or the slack was dressed a little better then IMO it would make an easier job.

 

[rolyberkin]

My issue with the Lewden boards is the advised torque settings, I have two torque drivers and with either if I torque them to manufacturers settings it has a tendency to damage the rcbo screws.

 

[Deleted member 26818]

Why is the up front RCD not time delayed?

 

[telectrix]

TT?

 

[Deleted account]

Agree with torque settings for screws.
Also I hate the main switch isolator on the right, much prefer left.
Anyone know why some boards have the main switch on the right?

Is it a TT system?
Just curious.

 

[Deleted account]

Two posts beat me to the answer before I asked the question. TT

 

[telectrix]

most boards have MS on the right. only one i've seen with it on the left is MK.

 

[Octopus]

For the money they are spot on ......................

 

[ruston]

For the money they are spot on ......................

What kind of money would that one be in the OP Murdoch ?

 

[SJD]

most boards have MS on the right. only one i've seen with it on the left is MK.

Crabtree.

 

[cliffed]

Why is the up front RCD not time delayed?

It’s a 100 ma time delay

 

[cliffed]

Agree with torque settings for screws.
Also I hate the main switch isolator on the right, much prefer left.
Anyone know why some boards have the main switch on the right?

Is it a TT system?
Just curious.

Yea it’s a tt system

 

[sparkdog]

I like them, quite well made.

 

[cliffed]

Don’t you think the bus bar system ,a bit dated,rather have the plug & play,like Schneider.

 

[Leesparkykent]

I didn't notice the upfront RCD, that's going to be a PITA for the customer in the event of a fault.

 

[suffolkspark]

@Leesparkykent its a time delayed one so "should" be ok, you can just see the S on the front of it.... The rcbos are only single pole though so there still isnt perfect discrimination and a fault remaining on the neutral will trip the whole supply... Not a great setup imo...

 

[Leesparkykent]

@Leesparkykent its a time delayed one so "should" be ok, you can just see the S on the front of it.... The rcbos are only single pole though so there still isnt perfect discrimination and a fault remaining on the neutral will trip the whole supply... Not a great setup imo...

Yes that was exactly my point. Neutral earth fault and the RCBO will trip but the upfront RCD, time delayed or not will still trip as the RCBO's don't break the neutral.

 

[cliffed]

Good point,they are usually supplied with earths,to solve that problem

 

[cliffed]

@Leesparkykent its a time delayed one so "should" be ok, you can just see the S on the front of it.... The rcbos are only single pole though so there still isnt perfect discrimination and a fault remaining on the neutral will trip the whole supply... Not a great setup imo...

Agree,could be a problem there

 

[MFS Electrical]

My issue with the Lewden boards is the advised torque settings, I have two torque drivers and with either if I torque them to manufacturers settings it has a tendency to damage the rcbo screws.

Do you have the pozi-flat hybrid type driver in your torque set? I do and have never had an issue with the Lewden RCBOs

 

[Deleted member 26818]

Think I would have kept the main switch and installed a 63A RCBO, rather than swapping the main switch for an RCD and using a 63A MCB.

 

[cliffed]

Yea,the problem is that the 63 amp breaker supplies a Loxone lighting panel,Rcbos in that Panel serves lighting .
So that was the purpose for the 100 ma td Rcd,discrimination for the other rcbos.

 

[suffolkspark]

Trouble is unless they are double pole rcbos then you have provided no discrimination.....

 

[Andy78]

How is fault protection provided for the 63A circuit ?

 

[suffolkspark]

How is fault protection provided for the 63A circuit ?

By the upfront rcd....

 

[Andy78]

By the upfront rcd....

I thought it was time delayed ? How will this meet disconnection times ?
Bear with me as I have nothing to do with TT systems and probably lack a lot of knowledge in this area.

 

[Wilko]

I thought it was time delayed ? How will this meet disconnection times ?
Bear with me as I have nothing to do with TT systems and probably lack a lot of knowledge in this area.

Hi - TT disconnection times for a distribution circuit is up to 1 second from Reg 411.3.2.4

 

[Andy78]

Hi - TT disconnection times for a distribution circuit is up to 1 second from Reg 411.3.2.4

Cheers for that. Thought I would be missing something. Didn't think the higher times applied to TT.
Every day's a school day.

 

[Deleted member 26818]

5s for non TT.

 

[cliffed]

This came with the rcb’os,providing a upfront Rcd is used,it’s ok-ish,I realise discriminating may not be ideal,but what else can you do,on a TT system.

 

[cliffed]

This came with the rcb’os,providing a upfront Rcd is used,it’s ok-ish,I realise discriminating may not be ideal,but what else can you do,on a TT system.

Trouble is unless they are double pole rcbos then you have provided no discrimination.....

yea,your talking about the N/E faults that may happen,discrimination will occur when there’s a L/E fault.
Who on earth uses double pole rcbo’s,.

 

[cliffed]

Notsure if this uploaded,this came with the rcbo’s

 

[suffolkspark]

But N/E faults are mighty common? Meaning that one ANYWHERE on that install will cause the upfront to trip loosing the entire installation.

imo that doesnt comply with the regs so either DP rcbos or an alternative design should have been considered.

Also imo on TT with a full rcbo board the 100ma S is not required upfront so youd actually be better off swapping that mcb for an rcbo and the upfronter to a main switch...

 

[cliffed]

Ok,but then neutral to earth faults will not be disconnected at all,they will remain,unless DP rcbo’s are used.
The reasoning for the time delay is,discrimination for the lighting panel,which have its own rcbo’s.

 

[suffolkspark]

But there is no discrimination because it will trip on a N - E fault?

 

[cliffed]

A neutral fault on that circuit,will trip the individual rcbo’s on the lighting panel,before tripping the time delay Rcd.

 

[cliffed]

Something I’ve read:

 

[suffolkspark]

Are you an electrician?

 

[cliffed]

Probably

 

[Leesparkykent]

A neutral fault on that circuit,will trip the individual rcbo’s on the lighting panel,before tripping the time delay Rcd.

yes but as Suffolk spark has said it will still trip the upfront RCD so there is no discrimination in the event of a neutral earth fault.

Neutral-earth fault=loosing every circuit.

 

[Leesparkykent]

This came with the rcb’os,providing a upfront Rcd is used,it’s ok-ish,I realise discriminating may not be ideal,but what else can you do,on a TT system.

yea,your talking about the N/E faults that may happen,discrimination will occur when there’s a L/E fault.
Who on earth uses double pole rcbo’s,.

Not double pole but switched neutral. These would of done the job.
Wylex NHXS1B32 32 Amp 30ma Type B 1 Module RCBO - Edwardes - https://www.edwardes.co.uk/en/products/wylex-nhxs1b32-32-amp-30ma-type-b-single-pole-1-module-rcbo-?utm_medium=google_shopping&utm_source=google&utm_campaign=google_shopping&gclid=EAIaIQobChMIxemvxrWc2wIVypPtCh23egO4EAQYASABEgLWBfD_BwE

 

[rolyberkin]

This came with the rcb’os,providing a upfront Rcd is used,it’s ok-ish,I realise discriminating may not be ideal,but what else can you do,on a TT system.

yea,your talking about the N/E faults that may happen,discrimination will occur when there’s a L/E fault.
Who on earth uses double pole rcbo’s,.

I do, TT quite common around here so I use an SBS board.

 

[cliffed]

Ok,if the fault happens on the 30ma protected circuits,theses would trip before the time delay Rcd.
That’s why the time delay Rcd is installed.
It’s no-different set up than the above literature supplied by the manufacturers.
I can see your points about the N/E scenario,thinking that would be the worst case.
When this set up was introduced years ago,it worked well,preventing complete disconnection, of power.

 

[cliffed]

Not double pole but switched neutral. These would of done the job.
Wylex NHXS1B32 32 Amp 30ma Type B 1 Module RCBO - Edwardes - https://www.edwardes.co.uk/en/products/wylex-nhxs1b32-32-amp-30ma-type-b-single-pole-1-module-rcbo-?utm_medium=google_shopping&utm_source=google&utm_campaign=google_shopping&gclid=EAIaIQobChMIxemvxrWc2wIVypPtCh23egO4EAQYASABEgLWBfD_BwE

Agree.

 

[Leesparkykent]

Ok,if the fault happens on the 30ma protected circuits,theses would trip before the time delay Rcd.
That’s why the time delay Rcd is installed.
It’s no-different set up than the above literature supplied by the manufacturers.
I can see your points about the N/E scenario,thinking that would be the worst case.
When this set up was introduced years ago,it worked well,preventing complete disconnection, of power.

You are literally talking milli seconds before the upfront RCD trips aswell as the RCBO. what's the installation method of the distribution circuit feeding the loxone?

 

[MFS Electrical]

Ok,if the fault happens on the 30ma protected circuits,theses would trip before the time delay Rcd.
That’s why the time delay Rcd is installed.
It’s no-different set up than the above literature supplied by the manufacturers.
I can see your points about the N/E scenario,thinking that would be the worst case.
When this set up was introduced years ago,it worked well,preventing complete disconnection, of power.

Yeah but even when the downstream RCBO trips the N-E fault will still remain and therefore will trip the main RCD after the time delay because the RCBO will only disconnect the line of the CCT the neutral and earth are still in the bars and the fault will be seen by the RCD main switch. IMHO the best way to sort it and achieve discrimination is to change the MCB to an RCBO and have an upfront isolator rather than a main switch.

 

[cliffed]

Not double pole but switched neutral. These would of done the job.
Wylex NHXS1B32 32 Amp 30ma Type B 1 Module RCBO - Edwardes - https://www.edwardes.co.uk/en/products/wylex-nhxs1b32-32-amp-30ma-type-b-single-pole-1-module-rcbo-?utm_medium=google_shopping&utm_source=google&utm_campaign=google_shopping&gclid=EAIaIQobChMIxemvxrWc2wIVypPtCh23egO4EAQYASABEgLWBfD_BwE

Agree.

 

[cliffed]

Yeah but even when the downstream RCBO trips the N-E fault will still remain and therefore will trip the main RCD after the time delay because the RCBO will only disconnect the line of the CCT the neutral and earth are still in the bars and the fault will be seen by the RCD main switch. IMHO the best way to sort it and achieve discrimination is to change the MCB to an RCBO and have an upfront isolator rather than a main switch.

Yea I can see where everyone is coming from,we are talking about a n/e fault here,I know it’s on aTT system,but realistically
These faults may be happening all the time,on most earthing systems,with negligible currents flowing.
N/e faults have always been a pain,& so be it if all power is disconnected,also if the rcbo disconnects that circuit surely that prevents any fault being on that circuit ie:N/E.,no current will flow to Earth ,arguing the fact the rcbo will trip on a N/E fault.
This is getting mighty confusing.