Do all MCBs fit all distribution boxes?

[Barking Mat]

My expérience they all fit on the din rails, but thé spacing for the terminals isn't thé same.

So the 'comb*' connecters don't fit.

*Don't know the british term.

 

[brightspark]

@sparkysy that's what surprised me, having done a load of CE, automotive etc., testing in the past if they're all passing the same standards then they should be compatible with each other. I'm surprised the spec doesn't include dimensioning of bus bars etc., then the physical incompatibility can be eliminated.

why would you make your gear to fit other manufacturers standard so people can use which ever they chose

My expérience they all fit on the din rails, but thé spacing for the terminals isn't thé same.

and why would you manufacture gear where everything is compatible you would soon be out of business people undercutting you

 

[pressbrake1]

Manufacturers see it as sport to obsolete their stuff . I think mem are the worst for it

 

[sako243]

why would you make your gear to fit other manufacturers standard so people can use which ever they chose

That's what standards are usually for, and are usually created by a consortium of manufacturers. Possibly slightly different in the MCB industry as everything is fairly simple. Then again consider batteries, AA, AAA and so on are all standardised in size and are compatible with each other yet there are multiple manufacturers. Just because a manufacturer can meet a standard doesn't mean they can't exceed it in some way and provide an edge over someone else.

 

[Dave-sparks]

MG changed their 3ph Dis boards a few years back, with zero backwards compatibility, & discontinued the old breakers

It was more than a few years, the last time that happened with MG would have been the change from the C45 range to C60 devices.

The current range is backwards compatible for all boards with C60 devices and Schneider will give written confirmation of this on request.

 

[Dave-sparks]

That's interesting as most of our 3 phase dis boards are Merlin from 20 years back. New Schneider breakers and RCBOs seem to fit OK.

Yes the new devices are backwards compatible and Schneider will give written confirmation on request.

 

[armalites]

Where I work one of the maintenance guys used to be a sparky, he listed 3 brands of MCB and said if you carried those 3 it would cover you for just about everything. Sadly I can't remember what they are

 

[armalites]

That's what standards are usually for, and are usually created by a consortium of manufacturers. Possibly slightly different in the MCB industry as everything is fairly simple. Then again consider batteries, AA, AAA and so on are all standardised in size and are compatible with each other yet there are multiple manufacturers. Just because a manufacturer can meet a standard doesn't mean they can't exceed it in some way and provide an edge over someone else.

Standards are great, they are like cakes/beers..... why would you have one when you can have two

 

[Brad93]

My expérience they all fit on the din rails, but thé spacing for the terminals isn't thé same.

So the 'comb*' connecters don't fit.

*Don't know the british term.

Busbar the comb shaped copper conductors

 

[skotl]

Appreciate all the responses. Given that a new MCB can be had for around a fiver I'll be sure to get one that matches what he's got.

 

[Misterg]

joe bloggs can fit them in there own property but its a fail on a test certificate till rectified

What category of fail?

(Asking for a friend )

 

[MetalMonkey]

What category of fail?

(Asking for a friend )

The reg covering this is 536.4.203, Note 2 especially.
Probably a C3 unless there is particular justification for a C2 (due to the way it is fitted or rating etc).

 

[Misterg]

Probably a C3 unless there is particular justification for a C2

Ta - so effectively an 'observation' rather than something that *must* be fixed?

I know that the plastic CU will generate something (C3?)

Never had an EICR done.

 

[MetalMonkey]

I know that the plastic CU will generate something (C3?)

Never had an EICR done.

Just being plastic shouldn't justify a code IMO, unless there is something else wrong or it is located (for example) under the stairs you would use as an escape route. Plastic was acceptable when it was installed. Can't judge work done to previous standards by the latest regs.

 

[Dave-sparks]

Ta - so effectively an 'observation' rather than something that *must* be fixed?

View attachment 429127
I know that the plastic CU will generate something (C3?)

Never had an EICR done.

All those devices are correct for that board as far as I can see, they are all from the same manufacturer and of the correct pattern to fit.

The plastic CU, if it is in good condition and not in an escape route would not warrant any code in my opinion.

The lack of RCD protection for the first 5 circuits would be a C3 (improvement recommended) as a minimum. This may be a C2 (potentially dangerous) depending on exactly what the circuits are for and how they are installed.

 

[Dave-sparks]

Can't judge work done to previous standards by the latest regs.

Yes you can, this is a common myth from a misunderstanding of a note in the regulations.

If something is considered to be dangerous or potentially dangerous by current regulations it gets coded regardless of whether it complied at the time of installation.

 

[Misterg]

All those devices are correct for that board as far as I can see, they are all from the same manufacturer and of the correct pattern to fit.

The plastic CU, if it is in good condition and not in an escape route would not warrant any code in my opinion.

The lack of RCD protection for the first 5 circuits would be a C3 (improvement recommended) as a minimum. This may be a C2 (potentially dangerous) depending on exactly what the circuits are for and how they are installed.

Thanks for that - the CU is near the side door, but there are 3 other doors to the outside.

Didn't realise that RCD protection was required for all circuits now. The non RCD are all lighting plus a dedicated supply to a doorbell transformer (!) and the supply to my shed which has a small CU with RCD protection (not really pressing for an answer, sorry - just idly wondering...)

 

[Dave-sparks]

Thanks for that - the CU is near the side door, but there are 3 other doors to the outside.

Personally I wouldn't mention it, but observations and their assigned codes are at the discretion of the person writing the report.

Didn't realise that RCD protection was required for all circuits now.

It's not required for all circuits but the number of things that do require it has increased to the point that it is effectively required for all domestic final circuits.

The doorbell transformer is unlikely to need it, unless the cable feeding it is buried in the wall or it's in a bathroom etc.

The feed to the shed may not need it, but it depends on the type of cable and how it is installed.

 

[Bornfree]

Crabtree are the odd one's out. They are completely different size mcbs and then they stop making them so unless you can find them in the correct rating on ebay it's change the board.

 

[Onoff]

Crabtree are the odd one's out. They are completely different size mcbs and then they stop making them so unless you can find them in the correct rating on ebay it's change the board.

Yep!