Type B or C MCB

[philipbg]

Can anyone help. At the moment I’m working on a library with about 11 power circuits for SSO & a CCTV/security system & 10 lighting circuits which are mostly track mounted LED spots & 2 fluorescent fittings all wired in T&E & MICC fed from a 125A TPN board. The spec calls for 10ka C type MCB or RCBO for fluorescent lighting & 10ka B type MCB or RCBO for power circuits. The problem is the make of dist board I have do not have in the country any B type RCBO so would it matter if I used C type RCBO which are off the shelf at any wholesaler. Plus do I really need RCBO for a library my understanding is if the area is supervised you can get away with MCB & RCBO are just for a house.

Thanks

 

[Sintra]

If the spec states B type then you have no option but to instal them.

 

[DurhamSparky]

RCBO are just for a house

you really need to read up on the regs matey!!

 

[ruston]

I would not be changing any of the specs without consulting the designer . You are leaving yourself wide open to any litigation.

You need to make the designer aware of your issues and let him resolve it.

 

[danzor]

RCBO's are only used when you cut the neutral short

 

[D80]

What make of board are you using? Seem to recall an issue in the past trying to get hold of a Type B RCBO for Square D boards. Could be well worth switching to use a different manufacturer!

 

[Simlec]

And read up on the differences between a type B & C !! Because if you don't know the difference then why are you working on a public sector building?

 

[kenny james]

What make of board are you using? Seem to recall an issue in the past trying to get hold of a Type B RCBO for Square D boards. Could be well worth switching to use a different manufacturer!

what fun i had today trying to get a bs3871 square d 40amp,

 

[Doomed]

what fun i had today trying to get a bs3871 square d 40amp,

Buy Fuses Online from The Fuse Company

 

[Engineer54]

Can anyone help. At the moment I’m working on a library with about 11 power circuits for SSO & a CCTV/security system & 10 lighting circuits which are mostly track mounted LED spots & 2 fluorescent fittings all wired in T&E & MICC fed from a 125A TPN board. The spec calls for 10ka C type MCB or RCBO for fluorescent lighting & 10ka B type MCB or RCBO for power circuits. The problem is the make of dist board I have do not have in the country any B type RCBO so would it matter if I used C type RCBO which are off the shelf at any wholesaler. Plus do I really need RCBO for a library my understanding is if the area is supervised you can get away with MCB & RCBO are just for a house.

Thanks

As Sintra has rightly pointed out, if your working on a project that has a ''Specification'' attached to the Contract, it must always be followed!! The only way you can alter any contract specification clauses is by means of an official ''Change Order''!!

This is by the sound of it a Public Building, It would also have gone through the LABC planning section for approval, i doubt if it would be cost effective to get a change order approved rather than changing you DB manufacturer. Unless of course the DB manufacturer was stipulated within the specification, then it would be quite a straight forward affair to get a change order for an RCBO type change!!

 

[ian.settle1]

I would not be changing any of the specs without consulting the designer . You are leaving yourself wide open to any litigation.

You need to make the designer aware of your issues and let him resolve it.

Not only that if you do not install as per spec you can be liable to replace all part which are not as the spec at your own cost.

 

[philipbg]

As the building is under local council control a skilledor instructed person would be trained or inducted into the council’sprocedures, i.e. don’t bang nails into the walls, no personal electrical itemallowed, etc. The use of all electrical equipment should have also been riskassessed. I see "skilled or instructed" persons (as referred to inBS7671:2008) only being present in commercial premises which this is classed asso the Duty Holder's job would be on the line if someone got a shock.
Therefore, with the site being under local council control no "ordinaryperson" would be getting up to any sorts of uncontrolled (and unsafe) workas in the case of domestics so RCBOs don’t have to be used but if I can sourceanother make I will still fit them. With the spec going out the window along time ago with the consultant being slung off the job it would not make adifference if the install changed from the original spec, which it has to keepthe council happy & as long as it complies with BS7671:2008.
I perfectly know the difference between the types of MCBs all I wanted toclarify is whether LED lights have the same tripping characteristics as fluorescencefittings which I doubted not having the same start up surge.

 

[Engineer54]

As the building is under local council control a skilledor instructed person would be trained or inducted into the council’sprocedures, i.e. don’t bang nails into the walls, no personal electrical itemallowed, etc. The use of all electrical equipment should have also been riskassessed. I see "skilled or instructed" persons (as referred to inBS7671:2008) only being present in commercial premises which this is classed asso the Duty Holder's job would be on the line if someone got a shock.
Therefore, with the site being under local council control no "ordinaryperson" would be getting up to any sorts of uncontrolled (and unsafe) workas in the case of domestics so RCBOs don’t have to be used but if I can sourceanother make I will still fit them. With the spec going out the window along time ago with the consultant being slung off the job it would not make adifference if the install changed from the original spec, which it has to keepthe council happy & as long as it complies with BS7671:2008.
I perfectly know the difference between the types of MCBs all I wanted toclarify is whether LED lights have the same tripping characteristics as fluorescencefittings which I doubted not having the same start up surge.

Really?? I wouldn't like to take any bet's on that. Councils tend to have a way of clawing back money on unsuspecting souls, that think they can change contractual specifications to suit themselves. I bet any changes that have been made to the original specifications on this project, have all been given the go ahead by the client, that being the Council dept in charge of this construction...

 

[GLENNSPARK]

As the building is under local council control a skilledor instructed person would be trained or inducted into the council’sprocedures, i.e. don’t bang nails into the walls, no personal electrical itemallowed, etc. The use of all electrical equipment should have also been riskassessed. I see "skilled or instructed" persons (as referred to inBS7671:2008) only being present in commercial premises which this is classed asso the Duty Holder's job would be on the line if someone got a shock.
Therefore, with the site being under local council control no "ordinaryperson" would be getting up to any sorts of uncontrolled (and unsafe) workas in the case of domestics so RCBOs don’t have to be used but if I can sourceanother make I will still fit them. With the spec going out the window along time ago with the consultant being slung off the job it would not make adifference if the install changed from the original spec, which it has to keepthe council happy & as long as it complies with BS7671:2008.
I perfectly know the difference between the types of MCBs all I wanted toclarify is whether LED lights have the same tripping characteristics as fluorescencefittings which I doubted not having the same start up surge.

so your going from a "B"..to a "C"...and you think it wont make any difference..lol....check out your time/current characteristics for b and c types first will you.......how do you know you will meet disconnection times here with a c type..as you propose?....do you not think that the designer would have taken this into account and specified the type of overcurrent to use at origin here?.....so lets all just deviate from the design....lets all just do as we like.........

 

[D80]

Are you insured to make this sort of design decision? If installed as per spec if it goes ---- up its someone else's problem. If you have made key changes, its your arse on the line.

They are paying for the work as per spec though, I don't see how you can change anything. If you can't get a type B for your preferred choice of board, get a board that you can. It's not really the biggest of asks.

I've had an issue in the past with Square D being able to do type B RCBO's. If they can't supply them, I go elsewhere. It's not a big ask really.