MPBC is it required

[cliffed]

During an Eicr noticed the remote garage got an up & over metallic door.. the garage got its own CU & relevant RCBO’s… No incoming services only the newly installed Garage Door which is controlled by remote… would you consider a MPBC to it

 

[buzzlightyear]

consider a MPBC to it

English man, English.

 

[cliffed]

English man, English.

Main Protective Bonding Conductor ..everything’s abbreviated these days…Soz

 

[loz2754]

No, unless it's likely to introduce a potential.

 

[cliffed]

No, unless it's likely to introduce a potential.

Ok… it’s a bit different from normal circumstances, being a possible internal & external situation on fault condition

 

[loz2754]

Is it in direct contact with the ground?

 

[Rockingit]

I think the roller mechanisms on these (the tank style pulleys) are often plastic for this reason. Just do a continuity test from cpc to the door, see what you get.

 

[cliffed]

Is it in direct contact with the ground?

It’s in contact with the ground & the rollers are metal too

 

[loz2754]

It’s in contact with the ground & the rollers are metal too

Then it needs bonding. By definition of an extraneous conductive part.

 

[Rockingit]

Then it needs bonding. By definition of an extraneous conductive part.

It may not be, though. If the controller / motor unit is class 2 (which I'd wager it is) then it's not an extraneous part. No different to the now infamous crittal window scenario. In fact I'd go so far as to suggest that by bonding it you could be introducing a potential hazard where none previously existed.

 

[cliffed]

It may not be, though. If the controller / motor unit is class 2 (which I'd wager it is) then it's not an extraneous part. No different to the now infamous crittal window scenario. In fact I'd go so far as to suggest that by bonding it you could be introducing a potential hazard where none previously existed.

Agree once again this topic always causes concern
MPBC if required would mean a TT system, it’s a report @ the moment & FI required

 

[mainline]

Agree once again this topic always causes concern
MPBC if required would mean a TT system, it’s a report @ the moment & FI required

A bit of testing would be an idea to ascertain if it is indeed extraneous.

 

[loz2754]

It may not be, though. If the controller / motor unit is class 2 (which I'd wager it is) then it's not an extraneous part

The motor is surely irrelevant, if there is a large lump of metal in contact with the ground (the frame of the roller shutter door) then it's most likely an extraneous conductive part (but would only require bonding if it's simultaneously accessible with any exposed conductive parts). There are other circuits in the CU, which may not be connected at the moment, but most likely will be at some point, probably including sockets.

It would be prudent to test it in any case.

For an EICR, I would suggest it's a C2 if it proves to be an ExtConPt.

 

[pc1966]

For an EICR, I would suggest it's a C2 if it proves to be an ExtConPt.

Why?

That seems a bit severe unless it is a specific situation (building site, marina, etc) where connection to a PME style of supply is prohibited.

 

[Rockingit]

The motor is surely irrelevant, if there is a large lump of metal in contact with the ground (the frame of the roller shutter door) then it's most likely an extraneous conductive part (but would only require bonding if it's simultaneously accessible with any exposed conductive parts). There are other circuits in the CU, which may not be connected at the moment, but most likely will be at some point, probably including sockets.

It would be prudent to test it in any case.

For an EICR, I would suggest it's a C2 if it proves to be an ExtConPt.

By that logic so is a garden gate!! My question remains - how, exactly, do you propose that this door is going to become part of an electrical circuit?

 

[westward10]

Why?

That seems a bit severe unless it is a specific situation (building site, marina, etc) where connection to a PME style of supply is prohibited.

PME is not prohibited on a building site.

 

[Rockingit]

PME is not prohibited on a building site.

I think that’s an ish at best! So whilst 704.411.3.1 does not specifically prohibit it - outright - it does seriously discourage it, though. My view is that this Reg exists to allow PME supplies to be delivered to sites to get them going (with subsequent ‘normal’ deployment once construction is complete) but with the intent to not use the CNE aspect and make a TT instead. I also assume that as soon as the much discussed change to mandate foundation earthing systems comes into play then this Reg will disappear completely as irrelevant. Maybe. Just my take on it.

Meanwhile, back to this imminently lethal garage door……

 

[loz2754]

Why?

That seems a bit severe unless it is a specific situation (building site, marina, etc) where connection to a PME style of supply is prohibited.

From the often quoted bpg4-

 

[cliffed]

By that logic so is a garden gate!! My question remains - how, exactly, do you propose that this door is going to become part of an electrical circuit?

Simultaneously accessible parts can be touched by a person, it’s internally & externally that could be the problem.Seeing industrial Roller Doors obviously these are actually attached to the main Metal Structure of the building which have a MPBC connected to it.

 

[pc1966]

Simultaneously accessible parts can be touched by a person, it’s internally & externally that could be the problem.Seeing industrial Roller Doors obviously these are actually attached to the main Metal Structure of the building which have a MPBC connected to it.

Is the main building a metal structure?

If so then it ought to be bonded via something adequate (10mm equivalent, etc) but the actual doors are probably in pretty good contact with that already. A nulled wander lead, etc, should establish that.