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

 

[mainline]

I do think with some extra finesse, he definitely could have hidden the cables.

View attachment 109179
View attachment 109178

The original tails are most defiantly buried and unless they are protected they won’t be compliant.

Did the meter tails originally goto an isolator ?.


The tails from the meter are very short.

I would have liked to have seen either an isolator or Sp+n fused unit there although not really allowed to use the cabinet for consumers gear.

 

[drewzh]

The original tails are most defiantly buried and unless they are protected they won’t be compliant.

Definitely buried and as every other cable in the house is run in a conduit of some kind, I can only assume they're compliant.

Did the meter tails originally goto an isolator ?.

Nope

The tails from the meter are very short.

I would have liked to have seen either an isolator or Sp+n fused unit there although not really allowed to use the cabinet for consumers gear.

I've never really liked the idea of having an isolator outside the house. We have UPS power supplies for our security system, but I still don't like the idea of someone having easy access to switch the power off

 

[mainline]

Definitely buried and as every other cable in the house is run in a conduit of some kind, I can only assume they're compliant.

Nope

I've never really liked the idea of having an isolator outside the house. We have UPS power supplies for our security system, but I still don't like the idea of someone having easy access to switch the power off

Thats no real excuse especially when you have exposed tails buried and clipped up walls.
You assume the tails are in conduit and I also assume that your assuming that the conduit is earthed.

Turning the power off in your case is made simpler by the fact you have no main fuse seals making it easy to pull the fuse.
I can’t believe the meter installer left the tails in blocks without even the thought of using an isolator, which would have been easier to fit and probably cheaper and left the seals intact.

 

[nicebutdim]

Getting back to the issue at hand, I'd rather protect surface clipped tails drilled straight through a wall, than have them buried. Bear in mind these are protected only buy a fuse rated between 60-100A, although I suspect original tails run a short distance up the cavity and aren't buried.

@Aaron b raises a point I'd tried to look into earlier, which is compliance of protective devices installed within tesla gen 3 wall connector. I didn't get to the bottom of whether or not it's compliant with BS7671 and it may well be - I simply can't find info on it.

 

[mainline]

Getting back to the issue at hand, I'd rather protect surface clipped tails drilled straight through a wall, than have them buried. Bear in mind these are protected only buy a fuse rated between 60-100A, although I suspect original tails run a short distance up the cavity and aren't buried.

Trunking or chased with metal plate.

 

[mainline]

There’s a pdf download for it Tesla gen 3
I didn’t get time to read it.
It's not compliant unless you fit a pen fault detection device.

 

[timhoward]

There’s a pdf download for it Tesla gen 3
I didn’t get time to read it.
It's not compliant unless you fit a pen fault detection device.

Agreed. In this case there is a DUA55 on the left.
It is the worst way to detect PEN faults (has a voltage limit range) but it complies.

 

[Aaron b]

One of the issues is if there's a manual test button and details like contact separation. The certificate of conformity for the charger should state it complies with BS EN 61008 or IEC 60755 etc. It would be much easier just to use a 61009 in the consumer unit. And even better to use a charger with PEN fault detection built-in.

 

[westward10]

In a lot of other countries 'All' soft skin cables must be installed in either a rigid plastic conduit, flexible plastic conduit or other suitable no conductive containment unless they are a special hi-tuff hard walled cable.
I know we have a love hate relationship with Copex style conduit in this country, but on a job like this where it is a work shop and you have single cables like that poking from a wall at worktop height I would have used Copex ( just my preference of course other conduits are available)

This is the UK and it is Kopex not Copex.

 

[nicebutdim]

This is the UK and it is Kopex not Copex.

Also the fact that 99% of what gets referred to as Kopex is not Kopex. The cheap carp sold by wholesalers offers little more protection than a slice of wet bread.

 

[MJPD29]

It's terrible, I would be ashamed to put my name to that.

That’s a bit dramatic

 

[Dustydazzler]

That’s a bit dramatic

Agree , I have seen far far worse installs in recent years , in fact I spend most of my working week putting right bodged installs or fixing faulty new works etc

 

[James]

Absolutely, not every job I do, would I want to be taking pictures of and showing off to people.

modern times with people showing off their instagram lives etc, we all know people only post there best look. Rare to see real world stuff.

sometimes, “make it work” is the only thing the customer wants/needs.
I am not saying that anything will do,
if I can’t upgrade “make it work” to make it work and make it safe then it’s not going to happen.
but sometimes looking nice is just not possible with the restrictions in place for that job.

 

[mainline]

That’s a bit dramatic

Do you really think that's a decent job, one that you would put your name to ?

It's pretty obvious to me that the original Cu was installed fairly competently, although an isolator instead of the henley blocks would have been a bonus and its only being assumed to be compliant.

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.

The cost and time would have been significantly reduced, not withstanding the aesthetics side of it.

 

[DPG]

Do you really think that's a decent job, one that you would put your name to ?

It's pretty obvious to me that the original Cu was installed fairly competently, although an isolator instead of the henley blocks would have been a bonus and its only being assumed to be compliant.

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.

Was there enough capacity in the original CU?

 

[mainline]

Was there enough capacity in the original CU?

It's fed by 25 mm tails and I assume its 100amp main switch.

 

[DPG]

It's fed by 25 mm tails and I assume its 100amp main switch.

Was there enough spare capacity to feed a 63A MCB though? Presumably that's why an extra unit was installed.

 

[mainline]

Was there enough spare capacity to feed a 63A MCB though? Presumably that's why an extra unit was installed.

It's never going to draw 100 amps for any length of time.

 

[DPG]

It's never going to draw 100 amps for any length of time.

No worries then. Wasn't sure what circuits they had in the original consumer unit. Might have had 2 showers or something.

 

[Dustydazzler]

Absolutely, not every job I do, would I want to be taking pictures of and showing off to people.

modern times with people showing off their instagram lives etc, we all know people only post there best look. Rare to see real world stuff.

sometimes, “make it work” is the only thing the customer wants/needs.
I am not saying that anything will do,
if I can’t upgrade “make it work” to make it work and make it safe then it’s not going to happen.
but sometimes looking nice is just not possible with the restrictions in place for that job.

Im in the same boat , if a customer wants £1000 worth of repairs for £500 I will do my best to see what i can do maybe cheaper materials for example , but at some point their just isn't enough money to actually do the job properly so I turn it down. However I guarantee someone will take on the job on the cheap for cash in hand and do a right old lash up of it...and probably a photo of lash up will one day end up on here

 

[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.