32A Commando Socket for 7kW charging
Discussion
A bit of background reading which describes why there is a potential issue with PME supplies & charging vehicles & although vehicles aren't specifically mentioned the fault mechanism is described:
https://professional-electrician.com/technical/pro...
Hots tubs often run off 32A Commando sockets & there the risk is managed by exclusion zones:
https://electrical.theiet.org/wiring-matters/years...
Obviously you can't achive isolation that way when charging a car so alternative methods are needed. Just because a Commando outlet is present doesn't mean you can plug any device with a Commando plug on it into it; there are specific & varying safety requirements as well. Hot tubs - separation, car chargers, PEN fault detection or an earth rod.
https://professional-electrician.com/technical/pro...
Hots tubs often run off 32A Commando sockets & there the risk is managed by exclusion zones:
https://electrical.theiet.org/wiring-matters/years...
Obviously you can't achive isolation that way when charging a car so alternative methods are needed. Just because a Commando outlet is present doesn't mean you can plug any device with a Commando plug on it into it; there are specific & varying safety requirements as well. Hot tubs - separation, car chargers, PEN fault detection or an earth rod.
ruggedscotty said:
No ideas for a name said:
The particular problem with earthing covers a tiny eventuality.
A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem..
Thing is electrical faults dont happen all that often. But when they do, they have the capability to do significant damage. hence the electrical regulations. geared to maintain a safe installation through the eventualities that can and do occur. if it can go wrong it will.A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem..
So no Im not one to be so dismissive about electrical faults.
through out history we have strived to make things as safe as possible. Your risk adverse profile may be less than someone else, or you may want to reduce cost as much as possible and take a punt on the issue not happening.
This happens and its why we regulate the use of electricity.
For clarity, I agree. I wasn't saying the risk is so small as to be ignored!
I was arguining against the posters in the thread that seem to say "Yeah go for it a Commando socket will be fine".
I really don't like to active disconnection devices... as far as I understand it, the requirement is to disconnect within 5s. In reality it will be much less and related to the drop out time on a contactor. However, that is a long time to be getting a shock if it all goes bad.
I don't understand the reluctance to add a TT earth. I understand the risk of hammering it through the gas pipe/drain/your own foot, but it isn't that hard to discover those services.
Mr Pointy said:
A bit of background reading which describes why there is a potential issue with PME supplies & charging vehicles & although vehicles aren't specifically mentioned the fault mechanism is described:
https://professional-electrician.com/technical/pro...
I know this is going off topic a bit... Thanks for that link.https://professional-electrician.com/technical/pro...
As it happens it covers the very point that I tried to check with two electricians last week.
Where the PME supply is extended to a detached outbuilding such as, for example, from a house to a detached garage, these bonding requirements will also need to be applied to any extraneous-conductive-parts in the garage. Given such circumstances, it is advisable to use a separate (TT) earthing arrangement for the installation in the detached building.
Both said no, it fine, just extend the PME from the house.
I know it is an EV section of the forum, but I enjoy the general electrical issues that get raised.
No ideas for a name said:
I know this is going off topic a bit... Thanks for that link.
As it happens it covers the very point that I tried to check with two electricians last week.
Where the PME supply is extended to a detached outbuilding such as, for example, from a house to a detached garage, these bonding requirements will also need to be applied to any extraneous-conductive-parts in the garage. Given such circumstances, it is advisable to use a separate (TT) earthing arrangement for the installation in the detached building.
Both said no, it fine, just extend the PME from the house.
I know it is an EV section of the forum, but I enjoy the general electrical issues that get raised.
Over in Homes & Gardens the issue of outbuilding earthing does come up occasionally & resident sparks contribute to those discussions. You may also know of John Ward & his Youtube channel - this one covers TT earth systems with reference to car charging, hot tubs & outbuildings but he has many other videos uploaded:As it happens it covers the very point that I tried to check with two electricians last week.
Where the PME supply is extended to a detached outbuilding such as, for example, from a house to a detached garage, these bonding requirements will also need to be applied to any extraneous-conductive-parts in the garage. Given such circumstances, it is advisable to use a separate (TT) earthing arrangement for the installation in the detached building.
Both said no, it fine, just extend the PME from the house.
I know it is an EV section of the forum, but I enjoy the general electrical issues that get raised.
https://www.youtube.com/watch?v=S5OtLg6voZY
Here's another one on earthing wrt to car chargers but note it is two years old so is subject to any chnages in regulations since then.
https://www.youtube.com/watch?v=gZVx7GbAwlg
Edited by Mr Pointy on Thursday 1st September 09:49
No ideas for a name said:
The particular problem with earthing covers a tiny eventuality.
A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
..and presumably you would have to be touching an actual bare metal part of the car ?A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
48k said:
No ideas for a name said:
The particular problem with earthing covers a tiny eventuality.
A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
..and presumably you would have to be touching an actual bare metal part of the car ?A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
in a salty atmosphere...
whilst wearing copper bottomed shoes
Again for clarity, I am not having a go at the poster.... it is 'unlikely' to occur.
However, I agree 100% with the real electricians posting above, and it needs to be installed in a way that combats that tiny risk.
It is a tiny additional cost to do it in a safe manner as opposed to a possibly risky manner.
I accept earthing is one of the 'bees in my bonnet'... along with not putting consumer side stuff in the meter box that is reserved for the DNO.
andy43 said:
That would explain why my installer fitted a separate metal unit with a RCBO switch rather than a RCB for the overcurrent protection OutInTheShed said:
No ideas for a name said:
As RuggedScotty says above, the standards keep changing.
That isn't a bad thing.. it is just that more is learned and more potential (no pun) problems are discovered.
EV charging is very much an evolving technology.
I do really think that AC charging will be a short lived system. Over the next say 10 years it will switch to DC connections with V2G being the norm.
The particular problem with earthing covers a tiny eventuality.
A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
The 'unicorn' devices which electronically disconnect the supply on PEN fault seem okay in theory, but one I looked at had a long disconnect time... It was just a contactor in a box with some control/detect circuitry... the contactor had a long drop out time.
But then we would be down to a fault on the network, whilst charging, whilst touching it, within the say .5s that it takes for the disconnect to occur.
I don't see the fact that 'chargers' can be bought with a 32A plug being a hole in the regulations. There are just special conditions for use.
It is only like selling for instance a hair dryer which says don't use in the bathroom. Each part (the device, and the outlet) are compliant on their own - there is just extra advice to make a particular situation safer.
I'm slightly confused about what faults will prevent an RCCB tripping when a grounded humanoid touches the somehow 'live' car body.That isn't a bad thing.. it is just that more is learned and more potential (no pun) problems are discovered.
EV charging is very much an evolving technology.
I do really think that AC charging will be a short lived system. Over the next say 10 years it will switch to DC connections with V2G being the norm.
The particular problem with earthing covers a tiny eventuality.
A broken neutral out in the network, BEFORE your property, in theory could cause your 'earth' and hence the exterior of the vehicle to rise to line voltage. It is very very unlikely. It has to occur whilst the car is on charge, and whiilst you are touching it to be a problem.
The 'unicorn' devices which electronically disconnect the supply on PEN fault seem okay in theory, but one I looked at had a long disconnect time... It was just a contactor in a box with some control/detect circuitry... the contactor had a long drop out time.
But then we would be down to a fault on the network, whilst charging, whilst touching it, within the say .5s that it takes for the disconnect to occur.
I don't see the fact that 'chargers' can be bought with a 32A plug being a hole in the regulations. There are just special conditions for use.
It is only like selling for instance a hair dryer which says don't use in the bathroom. Each part (the device, and the outlet) are compliant on their own - there is just extra advice to make a particular situation safer.
I really don't think these rules have anything to do with safety.
A pme supplied installation Or TN-C-S means that the terra earth is connected to the neutral, it is the same conductor...
if the neutral / earth conductor becomes detached broken then if the live is still connected then the current will flow through the loads in the house to the neutral terminal. this is connected to the earth at the supply intake. the earth bonds to all the metal work. and as the earth wire then becomes charged to a potential greater than the true muddy earth. this is a huge risk as anyone touching metal that is earthed to the supply earth and in contact with the ground could get a lethal shock.
The way that the RCD works though is that it detects an imbalance to earth. but where the earth and neutral are linked it would not go through the RCD. and it would not see a fault and it would not cut off the current.
ruggedscotty said:
ok....
A pme supplied installation Or TN-C-S means that the terra earth is connected to the neutral, it is the same conductor...
if the neutral / earth conductor becomes detached broken then if the live is still connected then the current will flow through the loads in the house to the neutral terminal. this is connected to the earth at the supply intake. the earth bonds to all the metal work. and as the earth wire then becomes charged to a potential greater than the true muddy earth. this is a huge risk as anyone touching metal that is earthed to the supply earth and in contact with the ground could get a lethal shock.
The way that the RCD works though is that it detects an imbalance to earth. but where the earth and neutral are linked it would not go through the RCD. and it would not see a fault and it would not cut off the current.
Yes I get that.A pme supplied installation Or TN-C-S means that the terra earth is connected to the neutral, it is the same conductor...
if the neutral / earth conductor becomes detached broken then if the live is still connected then the current will flow through the loads in the house to the neutral terminal. this is connected to the earth at the supply intake. the earth bonds to all the metal work. and as the earth wire then becomes charged to a potential greater than the true muddy earth. this is a huge risk as anyone touching metal that is earthed to the supply earth and in contact with the ground could get a lethal shock.
The way that the RCD works though is that it detects an imbalance to earth. but where the earth and neutral are linked it would not go through the RCD. and it would not see a fault and it would not cut off the current.
But it requires two faults. One of which would stop lots of things working properly in most circumstances.
And a car charger becomes very little different from any appliance in the house with an earthed metal chassis.
And identical to any outdoor electrical appliance?
I suppose the difference is, car chargers are going to be the most common electrical thing that the public use outdoors in all weathers.
But maybe all houses with certain Earth- Neutral connections need some additional fault detection, regardless of whether they have a car charger or not?
Exactly how many people have had a jolt from a granny charger?
In this context what's the difference between using a granny charger at 13A or a 15A or a 30A round plug?
Is the round plug perhaps safer because it plugs into a plastic thing with no exposed metal parts?
OutInTheShed said:
ruggedscotty said:
ok....
A pme supplied installation Or TN-C-S means that the terra earth is connected to the neutral, it is the same conductor...
if the neutral / earth conductor becomes detached broken then if the live is still connected then the current will flow through the loads in the house to the neutral terminal. this is connected to the earth at the supply intake. the earth bonds to all the metal work. and as the earth wire then becomes charged to a potential greater than the true muddy earth. this is a huge risk as anyone touching metal that is earthed to the supply earth and in contact with the ground could get a lethal shock.
The way that the RCD works though is that it detects an imbalance to earth. but where the earth and neutral are linked it would not go through the RCD. and it would not see a fault and it would not cut off the current.
Yes I get that.A pme supplied installation Or TN-C-S means that the terra earth is connected to the neutral, it is the same conductor...
if the neutral / earth conductor becomes detached broken then if the live is still connected then the current will flow through the loads in the house to the neutral terminal. this is connected to the earth at the supply intake. the earth bonds to all the metal work. and as the earth wire then becomes charged to a potential greater than the true muddy earth. this is a huge risk as anyone touching metal that is earthed to the supply earth and in contact with the ground could get a lethal shock.
The way that the RCD works though is that it detects an imbalance to earth. but where the earth and neutral are linked it would not go through the RCD. and it would not see a fault and it would not cut off the current.
But it requires two faults. One of which would stop lots of things working properly in most circumstances.
And a car charger becomes very little different from any appliance in the house with an earthed metal chassis.
And identical to any outdoor electrical appliance?
I suppose the difference is, car chargers are going to be the most common electrical thing that the public use outdoors in all weathers.
But maybe all houses with certain Earth- Neutral connections need some additional fault detection, regardless of whether they have a car charger or not?
Exactly how many people have had a jolt from a granny charger?
In this context what's the difference between using a granny charger at 13A or a 15A or a 30A round plug?
Is the round plug perhaps safer because it plugs into a plastic thing with no exposed metal parts?
Its the same issue with hot tubs and metal green houses etc.... once its outside the building its call an exported earth.
The install
Okay.... Someone installed a commando type socket here...
Any ideas on what happened... ?
Well the car was on charge... it was taking advantage of the nightly cheap rate. they were woken by a popping noise.
On investigation of the noise and burning smell they found an arcing fault in full swing in the garage.
No means to turn the power off other than break the seal and pull the boards fuse.
Once the power was off they were able to douse the flames and stop the fire. As with anything like this an investigation was carried out.
The findings were that there was a loose connection where the meter tails connected to the isolator in the distribution board. This caused the cable to heat up. with the heavy load of the charger for a few hours this resulted in the plastic insulation of the cables melting. and as they cables were close an arc developed that generated lots of heat melting the copper cables and setting fire to the surroundings.
The arc had actually travelled down the meter tails.
thoughts on this....
Those meter tails.... not well protected and also quite a run. these should have been protected.
The owner had wired in the extra socket. all proper and correct, however he did not check the consumer unit. If I was going to be drawing power for a charger id have been making sure that all the connections were properly torqued.
There was the initial issue that developed into an arc. Could an arc fault detector circuit breaker have picked this up ? very likely.
Use of a plastic consumer unit.... I install metal ones. If the regulations had been consulted then it would have been seen that it should have been protected by a non inflammable enclosure.
https://www.electricaldirect.co.uk/blog/a-guide-to...
id have had a double pole isolator beside the meter to enable the supply to be quickly isolated.
Id also install a soke / fire detector in the locale of the consumer unit
Most importantly Id regulate the electrical industry so that no one without the appropriate cetification and competency touches electrical installations.
ruggedscotty said:
The install
Okay.... Someone installed a commando type socket here...
Any ideas on what happened... ?
.....
The findings were that there was a loose connection where the meter tails connected to the isolator in the distribution board.......
Most importantly Id regulate the electrical industry so that no one without the appropriate cetification and competency touches electrical installations.
It's an illustration that the consumer has little protection from certain faults upstream of the consumer unit.
The OP was talking about using a Tesla Mobile Connector lead, via a 'Commando Socket'.
The Tesla lead it seems, is not just a lead with a plug on each end, it has a box in the middle which does some fault detection, including missing and fault grounds.
https://www.tesla.com/sites/default/files/download...
Saving a few quid by missing out that box may be foolish....
We nearly lost our house to an electrical fire.
Nothing to do with the wiring in the house or the load, just the main feed coming in the fuse was slightly loose.
The guy who fixed it said it was probably like it for years, just slowly getting hotter and hotter.
Have to say I was very impressed with the response from BG and SSEN we had a massive response truck outside the house in less than 15 minutes, and power back on in under 5.
Nothing to do with the wiring in the house or the load, just the main feed coming in the fuse was slightly loose.
The guy who fixed it said it was probably like it for years, just slowly getting hotter and hotter.
Have to say I was very impressed with the response from BG and SSEN we had a massive response truck outside the house in less than 15 minutes, and power back on in under 5.
The above surely just comes down to a maintenance issue? I'm sure everything was right and proper to deliver the 7kw load in terms of kit, but you have to check torque and cable terminations for any circuit designed to carry a continuous high load.
I maintain that for general use any correctly installed circuit for the zone it's in 'should' be safe for plugging in an on cable charger, but in addition to correct installation you have to maintain (check) the condition of that circuit. More than ever in a garage where condensation is a factor - any moisture at all across a hot live terminal will start to corrode.
It seems to me that by far the biggest danger of granny chargers in homes/garages is the continuous nature of the load. If you plug one in and go to bed, the reality is that's it's about to test the circuit you just plugged it into to a greater extent than anything else you would typically plug in around the house.
I maintain that for general use any correctly installed circuit for the zone it's in 'should' be safe for plugging in an on cable charger, but in addition to correct installation you have to maintain (check) the condition of that circuit. More than ever in a garage where condensation is a factor - any moisture at all across a hot live terminal will start to corrode.
It seems to me that by far the biggest danger of granny chargers in homes/garages is the continuous nature of the load. If you plug one in and go to bed, the reality is that's it's about to test the circuit you just plugged it into to a greater extent than anything else you would typically plug in around the house.
TheDeuce said:
The above surely just comes down to a maintenance issue?...
I doubt it.If that had ever been done up properly, the copper wires would show signs of having been compressed by the screw.
A lot of terminals seem to simply not get tightened properly.
Some things that contribute to this IMHO:
Carp design of fittings
Houses with electrics in hard to get at places, so the sparks is balanced on a ladder trying to do up a screw he can't see
electricians being a bit s
t and clueless. Too busy memorising TLAs and new names for the stripey wire to remember to tighten the terminals, if they haven't got too much RSI to do that anyway.Ever changing rules. Peope don't want to get a sparks in now, because the smallest change is an excuse to make them have a new CU. Kerrching.
OutInTheShed said:
TheDeuce said:
The above surely just comes down to a maintenance issue?...
I doubt it.If that had ever been done up properly, the copper wires would show signs of having been compressed by the screw.
A lot of terminals seem to simply not get tightened properly.
Some things that contribute to this IMHO:
Carp design of fittings
Houses with electrics in hard to get at places, so the sparks is balanced on a ladder trying to do up a screw he can't see
electricians being a bit s
t and clueless. Too busy memorising TLAs and new names for the stripey wire to remember to tighten the terminals, if they haven't got too much RSI to do that anyway.Ever changing rules. Peope don't want to get a sparks in now, because the smallest change is an excuse to make them have a new CU. Kerrching.
That's why all such terminations in an installation have to remain accessible, for maintenance. The exception is clamp sprung terminations such as wago boxes designed to be buried in a wall and forgotten about, the theory being that they will retain pressure on the copper for the life of the wiring.
If you buy a new house and pull all the sockets you'll often find some wires often slip straight out, because the copper has relaxed around the initial pressure put upon it.
If anyone has a perfectly installed charger or socket to be used for charging installed by a top rate spark - they should still open it up and check the terminals once a year, especially if in a garage.
OutInTheShed said:
TheDeuce said:
The above surely just comes down to a maintenance issue?...
I doubt it.If that had ever been done up properly, the copper wires would show signs of having been compressed by the screw.
A lot of terminals seem to simply not get tightened properly.
Some things that contribute to this IMHO:
Carp design of fittings
Houses with electrics in hard to get at places, so the sparks is balanced on a ladder trying to do up a screw he can't see
electricians being a bit s
t and clueless. Too busy memorising TLAs and new names for the stripey wire to remember to tighten the terminals, if they haven't got too much RSI to do that anyway.Ever changing rules. Peope don't want to get a sparks in now, because the smallest change is an excuse to make them have a new CU. Kerrching.
I'm not sure there were many rules around then.Eveything else in the house had been replaced a few years back.
OutInTheShed said:
TheDeuce said:
The above surely just comes down to a maintenance issue?...
I doubt it.If that had ever been done up properly, the copper wires would show signs of having been compressed by the screw.
A lot of terminals seem to simply not get tightened properly.
Some things that contribute to this IMHO:
Carp design of fittings
Houses with electrics in hard to get at places, so the sparks is balanced on a ladder trying to do up a screw he can't see
electricians being a bit s
t and clueless. Too busy memorising TLAs and new names for the stripey wire to remember to tighten the terminals, if they haven't got too much RSI to do that anyway.Ever changing rules. Peope don't want to get a sparks in now, because the smallest change is an excuse to make them have a new CU. Kerrching.
being s
t and clueless... yeah... take it you hate it when you cant do something yourself and you have to get in a spark Anyway as said doing your testing after an install brings up issues... someone thats actually a spark and not some flyboy you found on gumtree etc... Would have found the Ze and Zs readings not too good.... ever changing rules tend to be through hard experience learns and these filter through. like we have had with earth rods and the unicorn relay, now that they can detect a broken neutral they dont need an earth rod local. IF THERE IS THE PROTECTIVE DEVICE. If not then its thump in a rod etc...
people dont want to get in sparks now... But thing is the average joe really isnt capable of putting in and adhering to all the regulations etc. and its not there for the sake of being there.
That plastic box.... should have been either metal or it should have been enclosed in a fire proof enclosure. thats actually part of the fire requirements... That copper pipe to the right.... if thats a gas pipe it contravenes the regs as the pipe is less than 1.5m from the consumer unit....
Aye
TheRainMaker said:
...
Have to say I was very impressed with the response from BG and SSEN we had a massive response truck outside the house in less than 15 minutes, and power back on in under 5.
We had an issue with a looped supply going bang (literally) in the lane next to us. Sunday morning response from WPD.Have to say I was very impressed with the response from BG and SSEN we had a massive response truck outside the house in less than 15 minutes, and power back on in under 5.
Van number one within about 15 minutes, then more vans, some pickups then an excavator within an hour. Trench opened, cable jointed and back filled... They even replanted the grass verge with grass seed. I think we were offered a generator truck too...
Our son hit a cable in his garden with an excavator whilst building his garage (cable wasn't on the map as it should have been)... Friday response, WPD there to make sure everyone was safe.. then trucks just kept arriving through the day. Ended up with a road closure and temporary traffic light for three days whilst they re-routed the cables.
I have to say the guys work damn hard, and I am very impressed.
Back on the thread... either of those external events could have caused a PEN fault.. ours would have affected just a few houses, the other was the main feed to half a village. External events can bite you.
ruggedscotty said:
I wonder....
That plastic box.... should have been either metal or it should have been enclosed in a fire proof enclosure. thats actually part of the fire requirements... That copper pipe to the right.... if thats a gas pipe it contravenes the regs as the pipe is less than 1.5m from the consumer unit....
Aye
The plastic box would have been fine when installed, and AIUI would in itself still be fine today as an existing installation?That plastic box.... should have been either metal or it should have been enclosed in a fire proof enclosure. thats actually part of the fire requirements... That copper pipe to the right.... if thats a gas pipe it contravenes the regs as the pipe is less than 1.5m from the consumer unit....
Aye
The IET only changed to wanting metal consumer units some time in the last ten years?
If you go back say 20 years, was it even possible to buy a metal CU? Were they even allowed?
OutInTheShed said:
ruggedscotty said:
I wonder....
That plastic box.... should have been either metal or it should have been enclosed in a fire proof enclosure. thats actually part of the fire requirements... That copper pipe to the right.... if thats a gas pipe it contravenes the regs as the pipe is less than 1.5m from the consumer unit....
Aye
The plastic box would have been fine when installed, and AIUI would in itself still be fine today as an existing installation?That plastic box.... should have been either metal or it should have been enclosed in a fire proof enclosure. thats actually part of the fire requirements... That copper pipe to the right.... if thats a gas pipe it contravenes the regs as the pipe is less than 1.5m from the consumer unit....
Aye
The IET only changed to wanting metal consumer units some time in the last ten years?
If you go back say 20 years, was it even possible to buy a metal CU? Were they even allowed?
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