Do these internally exposed meter tails require mechanical protection?

[drewzh]

Hi,

I was hoping someone with a little more insight might be able to shed some light on a potential issue I have, as I can't seem to find another example online where this specific question that has been answered.

What you can see in the attached photograph is meter tails (single insulated + sheathed), coming in to supply an EV distribution board. It seems from research that most installations are buried with additional conduits for protection, so I'm not sure what the specific rules are around clipped-direct meter tails.

The regs are a little hazy, but should these tails, being situated in a garage workshop, in close proximity to daily tool usage and storage, have further mechanical protection, in the form of metal conduit, or is this perfectly reasonable for a new install?

Many thanks in advance,
Drew

 

[davesparks]

There was no need for those tails at all, as they could have taken a supply from the Consumer unit, there is a spare way to take a 63amp mcb and side entry would have been simple.

Feeding a CU from an MCB is bad practice as it gives little to no chance of selectivity.

 

[mainline]

Feeding a CU from an MCB is bad practice as it gives little to no chance of selectivity.

It's a better alternative to having those tails running up the wall.

And selectivity between what ?

 

[DPG]

It's a better alternative to having those tails running up the wall.

And selectivity between what ?

Between an OCPD tripping in the original CU as opposed to the new one.

 

[mainline]

Between an OCPD tripping in the original CU as opposed to the new one.

He's got a 40amp in the LV and a proposed 63amp in the main cu.

There is partial selectivity between two MCBs up to the selectivity
limit current if the downstream MCB has a lower rated current than
the upstream MCB

 

[davesparks]

It's a better alternative to having those tails running up the wall.

The surface installation of tails complies with the regulations but disregarding selectivity does not.

And selectivity between what ?

Between protective devices, the 63A mcb will not achieve any selectivity with the downstream MCB's.

 

[DPG]

He's got a 40amp in the LV and a proposed 63amp in the main cu.

There is partial selectivity between two MCBs up to the selectivity
limit current if the downstream MCB has a lower rated current than
the upstream MCB

That's not enough to give much selectivity though. Probably better in this case to split the tails as they have done in this case.

 

[westward10]

Can't believe this is pushing 70 posts for something that essentially just looks bad.

 

[nicebutdim]

Can't believe this is pushing 70 posts for something that essentially just looks bad.

We've moved on to suggesting options for poor design.

 

[mainline]

The surface installation of tails complies with the regulations but disregarding selectivity does not.

That's not true, there is partial selectivity if the downstream MCB has a lower rated current than the upstream MCB

There are already rcbos downstream of the 40 amp MCB, so does that mean there is no selectivity ?? Even using tails ?

Between protective devices, the 63A mcb will not achieve any selectivity with the downstream MCB's.

Not true.


Also bear in mind that these boards are next to each other.

 

[nicebutdim]

Also bear in mind that these boards are next to each other.

That's a fair point.

 

[westward10]

We've moved on to suggesting options for poor design.

Next thing we'll have 50 odd posts for what drill should I use.

 

[James]

Next thing we'll have 50 odd posts for what drill should I use.

stick with the ones that go round and round, I have always found them ok.

 

[rewireIT]

stick with the ones that go round and round, I have always found them ok.

Bit and brace?

 

[pirate]

73 posts on this?
FFS, if you don't like how it looks, cover it up!

 

[mainline]

Next thing we'll have 50 odd posts for what drill should I use.

I don't care as long as it's not mine.

 

[mainline]

That's not enough to give much selectivity though. Probably better in this case to split the tails as they have done in this case.

How about something like this with the outbuildings MCB omitted.

73 posts on this?
FFS, if you don't like how it looks, cover it up!

Or design it properly in the beginning.