dobbslc
Forum Supporter
- Messages
- 13,074
- Location
- Hertfordshire UK
What's different about an EV charge point that a normal MFT can't test?
- Thread starter Onoff
- Start date
addjunkie
Member
- Messages
- 13,653
- Location
- Northumberland. Reet oot in the sticks
Use really really strong string in the duct….nothing more annoying than a big cable and a snapped string
brightspark
Member
- Messages
- 41,232
- Location
- yarm stockton on tees
just wired one up 2 day in 3 core swa and seperate cat 5 cable for the ct clamp , no need for it to go in the db . got another 2 to extend the cables on another job and move the position of the chargers
Onoff
In the land of the unfinished project I am King!
- Messages
- 12,671
- Location
- Sevenoaks, UK
Can always borrow a ferret round here!
Onoff
In the land of the unfinished project I am King!
- Messages
- 12,671
- Location
- Sevenoaks, UK
Thanks all. I know loads more than I did 24 hours ago!
More questions then:
I've read it's perhaps not the best idea to have a 32/40A breaker running flat out for many hours in the main cu. Can't think of any domestic loads that size that would be running like that long. Just glad we don't have a leccy shower given the time my kids spend in the bathroom mind...
Not that I've space for another breaker in the current board. The only way that'll happen is if I change the board to a bigger one.
The other way is Henleys and a separate EV cu, probably this to match the cu:
Having the EV opd in the main cu though would save on the SPD, SPD MCB and DP switch.
Ideally the meter has to move to the right, the incomer could do with going right and lower, that is I'm sure not a goer.
So to get another MCB in I'd have to change the board. Not insurmountable and everything could be transplanted over and the meter moved but just a ball ache.
I could change the current 100A DP main switch in the house cu, (if bigger), to a DP Type S 100mA RCD. Then a 40A breaker for the EV charger. As TT that'd protect the outgoing SWA. No selectivity issue then either with the RCD in the charger.
Beginning to think there is just not enough space on that current layout.
More questions then:
I've read it's perhaps not the best idea to have a 32/40A breaker running flat out for many hours in the main cu. Can't think of any domestic loads that size that would be running like that long. Just glad we don't have a leccy shower given the time my kids spend in the bathroom mind...
Not that I've space for another breaker in the current board. The only way that'll happen is if I change the board to a bigger one.
The other way is Henleys and a separate EV cu, probably this to match the cu:
EV Consumer Unit 100A Switch + 32A DP RCBO (Type A) + SPD - IP20 | Fusebox (EV32AX)
www.tlc-direct.co.uk
Having the EV opd in the main cu though would save on the SPD, SPD MCB and DP switch.
Ideally the meter has to move to the right, the incomer could do with going right and lower, that is I'm sure not a goer.
So to get another MCB in I'd have to change the board. Not insurmountable and everything could be transplanted over and the meter moved but just a ball ache.
I could change the current 100A DP main switch in the house cu, (if bigger), to a DP Type S 100mA RCD. Then a 40A breaker for the EV charger. As TT that'd protect the outgoing SWA. No selectivity issue then either with the RCD in the charger.
Beginning to think there is just not enough space on that current layout.
MetalMonkey
Member
- Messages
- 3,269
- Location
- UK
AFAIK The EV adapters you get for the MFTs basically simulate having a car connected to the charger so you can test the outputs of the charger and simulate a fault to check it.
MetalMonkey
Member
- Messages
- 3,269
- Location
- UK
A lot of chargers now are incorporating open PEN protection, in which case an earth rod is not required for TN-C-S (PME).
I wish I did. Its like a foreign language in here.
I can usually follow most things but much of this is double Dutch. Not sure if if it's the bottle of Red I treated myself to, or it really is as complicated as it sounds
No wonder my son struggled with his city and guilds exam with no tuition. Lol
Anyway I will catch up tomorrow when I have totally thwarted my phobia.
Onoff
In the land of the unfinished project I am King!
- Messages
- 12,671
- Location
- Sevenoaks, UK
I've posted this before but I heard a story about the outgoing head of the Institution of Electrical Engineers. Every year at their annual dinner he gave a blinding after dinner speech. Full of electrical related stories and witty anecdotes. As he started his speech every year he'd pull out a piece of crumpled paper, glance at it then launch into it, periodically glancing at the bit of paper. Someone cottoned in it was the same bit of paper every year.
When he retired, his replacement, nervous of his own upcoming speech, asked what was written on the piece of paper. It said:
"Red wire live, black wire neutral".
What MetalMonkey says. It simulates the different communication states the car has with the charger and the charger should respond in a certain way and then cut off the power to the car under certain conditions, you're confirming that happens with the adapter.
It lets you test (with your MFT) the internal RCD within the charger too.
It was due to the risk of a broken neutral on the suppliers side (not as uncommon as you'd hope). In the event of this happening all earthed metal work rises to dangerous voltages which isn't so bad inside your house when you're within the equipotential zone but move things outside where you're stood on the ground, possibly wet ground, and you touch the car body that has risen to a dangerous voltage and you're at zero volts you become the earth path.
Rodding the charger and having the rod close to the car eliminated this from happening should the suppliers neutral fail.
Newer charges with built in PEN protection sense this and cut off all conductors including the earth, completely isolating the car from the electrical installation.
There's movement to all new electrical installations (whether they have chargers or not) having their own earth rods as a result of broken neutrals in TNC-S supplies, this is putting the onus onto electrical installers/designers rather than holding the DNOs and there shoddy networks to account.
Onoff
In the land of the unfinished project I am King!
- Messages
- 12,671
- Location
- Sevenoaks, UK
Not forgetting the money they'll save not having to upkeep/maintain that side of the infrastructure. Shareholders will be happy.
BT with their move away from copper landlines is no different. Ancient copper lines they either can't or don't want to upkeep. Every time it rains the phone service degrades, flooded junction boxes etc. EE hybrid router things going in around here instead, now the service drop outs and the phone doesn't work during a power cut.
daedalusminos
Member
- Messages
- 2,330
- Location
- Norwich
Just a word of warning about how built in PEN fault protection is usually implemented...the EVSE constantly monitors the line voltage and checks to ensure it's within the statutory requirements, in the UK 230V +10%,-6% (216V to 253V), if it falls outside these limits for more than 5secs (I think) it isolates the power to the vehicle. If done correctly the manufacturer should inset the measurment limits to account for manufacturing tolerances, temperature and drift over lifetime. If your supply is close to the limits then it's possible you'll exhibit false triggering of the protection circuit.
Onoff
In the land of the unfinished project I am King!
- Messages
- 12,671
- Location
- Sevenoaks, UK
The local overhead infrastructure has recently been upgraded after many, many years of brown outs, power dips etc. I'd often been out walking along the valley & heard the repair crews saying to each other there wasn't really enough slack in whatever to repair or that the whole lot needed replacing etc. Touch wood it's been really stable since. The whole process was really well managed with notice given, pre site inspections on every property and great liaison. At the same time they undertook lots of tree trimming. All my neighbours and I are pretty happy tbh. Had a little bit of an issue when I told the surveyor I wanted my previously, damaged and repaired overhead replaced from pole to house. They'd spliced it as an emergency repair, crimped and taped some years ago when a tree rubbed through it. He wasn't sure if they would do it or not so I emailed and held them to their statement that they were going to be replacing all (their) overhead cables. Came home from work to be met by the gang supervisor waiting for me. Wanted me to look at what they'd done, was I happy etc before they energised it. Really nice guys, all from Wales / Anglesey. Worked 24/7 to get it all done.
With hindsight I'd have had them shift the head and meter
