16mm T&E tails on 100amp fuse

[haptism]

Did a job earlier in a new build, part of a 5 year old new build estate in the darkest depths of kent. Anyhow opened up CU and saw 16mm tails so assumed would be on 80a fuse as there not huge demand. Then outside to check service head and main fuse is labelled 100a ?, the tails are 16mm t&e.
I did nor remove the fuse carrier to check the actual fuse as it was sealed

Anyhow my point is, ive already installed new circuit and have to issue an EIC, I will be writing in comments box write what I found and that it looks wrong. However looking forward what should I do about this. The customer wont be happy me turning off all the power; I told him to contact the people he bought the house from and raise the point.

Another thing I found includes a spur that don't switch off the load in garage that its labelled to do. Its not right is it, brand new house as well, and theres hundreds of them.

 

[Andy78]

Earthing conductor and bonding arrangements immediately ring some alarm bells ....

 

[haptism]

Earthing conductor and bonding arrangements immediately ring some alarm bells ....

There is acceptable Ze, main earth at the board is single g/y 16mm, water and gas bonded with 10mm also.

 

[Andy78]

There is acceptable Ze, main earth at the board is single g/y 16mm, water and gas bonded with 10mm also.

Next thing I would worry about is did the cable run need RCD protection due to the nature of the install ?

The service fuse carrier is always marked 100A as the max rating of fuse. The fuse would need to be checked to ascertain if the tails need fusing down after it.

 

[Deleted member 26818]

Measure the PFC and then conduct the Adiabatic equation, to determine whether the conductors are under sized.

 

[DPG]

What is the FCU supposed to switch off in the garage?

 

[haptism]

What is the FCU supposed to switch off in the garage?

x1 garage socket

 

[Deleted member 26818]

Probably just wired up the FCU incorrectly.
Most likely find the FCU is now switching the ring rather than the socket.

 

[haptism]

Measure the PFC and then conduct the Adiabatic equation, to determine whether the conductors are under sized.

Looks like a separate 16mm main earth is run alongside the t&e, I cannot see if the t&e is mechanically protected on way to cu but I doubt it, so yeh, no rcd for that added to the list. I will need to take fuse out of carrier and have a look, maybe its 80A afterall. Yeh PFC looks good, don't have results to hand.

 

[luka B]

Looks like a separate 16mm main earth is run alongside the t&e, I cannot see if the t&e is mechanically protected on way to cu but I doubt it, so yeh, no rcd for that added to the list. I will need to take fuse out of carrier and have a look, maybe its 80A afterall. Yeh PFC looks good, don't have results to hand.

I had one last week where Main fuse blew twice in a week .. was replaced by electric co. I thought maybe the cause was too much usage ... Took the Main Fuse ( no seal ) ... but alas it was a grey fuse with no writing on it !! so i was none the wiser .

 

[Strima]

Note on the cert stating you're unable to verify the size of the DNO fuse.

Not your place to start pulling fuses. You may contact the DNO to find out but they probably don't know either.

 

[haptism]

Note on the cert stating you're unable to verify the size of the DNO fuse.

Not your place to start pulling fuses. You may contact the DNO to find out but they probably don't know either.

Yes I will be doing that, lesson learnt today, check service head before any works done, not afterwards.

 

[haptism]

Next thing I would worry about is did the cable run need RCD protection due to the nature of the install ?

The service fuse carrier is always marked 100A as the max rating of fuse. The fuse would need to be checked to ascertain if the tails need fusing down after it.

Theres definitely no rcd protecting the tails; my issue is I cannot see if the t&e is mechanically protected or not when it goes into building so will note this on the cert also. Is it usual to run tails in t&e on new builds and put in conduit ?? That's a really subjective question.

Second thoughts its a lash up, t&e comes out switch fuse (also stating 100A) through a bush and ring, theres no gland; hangs in the air with no fixings then goes into the wall. Lash up if you ask me

 

[Toneyz]

Looks like a separate 16mm main earth is run alongside the t&e, I cannot see if the t&e is mechanically protected on way to cu but I doubt it, so yeh, no rcd for that added to the list. I will need to take fuse out of carrier and have a look, maybe its 80A afterall. Yeh PFC looks good, don't have results to hand.

Is this T&E that goes to the C.U. a sub main?

 

[haptism]

Is this T&E that goes to the C.U. a sub main?

Im not entirely sure as all wiring is back entry into CU, proper tails go from main DNO Fuse to meter and then to switch fuse; from the switch fuse its t&e. So I assume yes it goes to CU

 

[Toneyz]

Im not entirely sure as all wiring is back entry into CU, proper tails go from main DNO Fuse to meter and then to switch fuse; from the switch fuse its t&e. So I assume yes it goes to CU

So there is a switch fuse protecting a sub-distribution circuit (sub-main) is this fused down to 60A?. The other issue is the method of its installation.

 

[haptism]

So there is a switch fuse protecting a sub-distribution circuit (sub-main) is this fused down to 60A?. The other issue is the method of its installation.

Its not a sub main, its a semi detached house with its own single phase supply. The switch fuse is there as the tails are longer than 3m, the load side of the switch fuse is t&e which I can only assume is going the the CU. The switch fuse has 100a on it

 

[Strima]

If it's a switch fuse the consumer side of the meter then you can remove the fuse to check.

 

[haptism]

If it's a switch fuse the consumer side of the meter then you can remove the fuse to check.

Yeh I will do tomorrow

 

[haptism]

But still the tails not rcd'd

 

[Toneyz]

Yeh I will do tomorrow

post up some photo's so we know what you are describing.

 

[Toneyz]

If you are saying that the meter tails are 16mm from the switch fuse with hopefully a 60A fuse that is perfectly acceptable as long as certain criteria is met overcurrent is afforded by the 60A fuse so just need to ensure there is short circuit protection.
It is the same principle that you find when switch-fuses are joined onto a bus-bar chamber.

 

[Dave OCD]

I'd say that by virtue of the switch fuse being present the 16mm T&E is a sub-main. I'd just check the fuse in that and fit a 60a cartridge if necessary. And it's only recently that this sub-main requires RCD protection to be compliant [Assuming reasonably low Ze] so in my opinion that doesn't make it dangerous. Just note it on the certificate.

 

[haptism]

I'd say that by virtue of the switch fuse being present the 16mm T&E is a sub-main. I'd just check the fuse in that and fit a 60a cartridge if necessary. And it's only recently that this sub-main requires RCD protection to be compliant [Assuming reasonably low Ze] so in my opinion that doesn't make it dangerous. Just note it on the certificate.

Okay, never considered that would be called a submain so that's good info. Will check tomorrow when the house was constructed but im sure it no older than 5 years.

 

[Toneyz]

The regulation regarding a cable buried within the wall at a depth equal or less than 50mm being RCD protected has been around from at least 2008 17th edition reg 522.6.6 refers.

 

[GLENNSPARK]

Did a job earlier in a new build, part of a 5 year old new build estate in the darkest depths of kent. Anyhow opened up CU and saw 16mm tails so assumed would be on 80a fuse as there not huge demand. Then outside to check service head and main fuse is labelled 100a ?, the tails are 16mm t&e.
I did nor remove the fuse carrier to check the actual fuse as it was sealed

Anyhow my point is, ive already installed new circuit and have to issue an EIC, I will be writing in comments box write what I found and that it looks wrong. However looking forward what should I do about this. The customer wont be happy me turning off all the power; I told him to contact the people he bought the house from and raise the point.

Another thing I found includes a spur that don't switch off the load in garage that its labelled to do. Its not right is it, brand new house as well, and theres hundreds of them.

The distributers protection (service head bullit) on a condition report should normally be recorded as a "LIM"...

Next, use your intuition to determine what the max. Demand for each supply is/should likely be...
P.S.
It won't be 80 chuffin amps...thats for sure...


The bigger issue here for me...is whether or not it complies with the requirements of certain DNO's in regards to length of run from the service head (usually 3 meters...i think)...

 

[DPG]

The bigger issue here for me...is whether or not it complies with the requirements of certain DNO's in regards to length of run from the service head (usually 3 meters...i think)...

It's fed from a switch fuse though.

 

[GLENNSPARK]

It's fed from a switch fuse though.

So then I can't understand what he's Bleating about...

 

[davesparks]

Its not a sub main, its a semi detached house with its own single phase supply.

Submain Is the common name for any distribution circuit which is part of the consumers installation. The type of property or incoming supply is irrelevant, if it is a circuit with ocpd etc on the consumers side of the meter and it feeds a DB, CU etc then it is a submain.

 

[haptism]

Checked again today and switch fuse has an 80A. Took some pics of the t&e serving the CU, as you can see theres no glands, no cleats, no rcd to be found. Not sure if theres mechanical protection where the t&e goes into building; what are your thoughts on this. The building was constucted in 2016.