Just had a look into some EV charging issues someone is having.
EVSE was installed just before Christmas.
Had a quick look but it was raining heavily. It's a good distance - at least 30m as the crow flies - from the house.
It's on 2.5mm^2 T&E. It seems to allow 32A charging. Already alarm bells.
The owner also complained about lights dimming in the house...
So I measured the voltage under base load in the house. 205V.
Turn the hobs and oven on, and we're <200V.
Plugged in a light 50W ish load into the EVSE (janky EVSE simulator), and it's down at 195V. I can see that getting into the 180V region.
Super dodgy.
@cybergibbons FWIW, the company that did mine used 6mm^2 for a 7m run because "It saves doing voltage calculations and we get fewer callbacks"
@wishy a single callback can wipe out all profit on a job. Understandable.
@cybergibbons @wishy
Looked over some issues at a friend’s house a few years back. They’d three electric showers, not just pumped but heated too. All lights in lower floor were out too. Only one shower worked, a second failed when turned on (neon in isolator blinked), third was in a non-functioning bathroom. The blinky shower was wired from an old isolator with no clamp screws remaining on the live term. The lighting circuit was dead cos the consumer unit bus bar finger was gone, arced to oblivion (I suspect that was a manufacturing issue with the breaker). Added up load incl 3 showers & the supply fuse wouldn’t carry it. Called in a pro.
They kept one electric shower, replumbed with main pressure hot water & two pump showers. Partial rewiring with two new consumer units.
@guardeddon @wishy sounds like a fire avoided there TBH.
@cybergibbons @wishy
Definitely!
And the environment around the CUs was a literal tinderbox as there was a hoarding habit.
Didn’t get the backstory but suspect it was a consequence of well meaning but incompetent bodgers.
@guardeddon @wishy I am not sure people really know how much heat a badly wired connection on 16A or 32A can make.
@cybergibbons @wishy
I have another horror story from a church hall. Single phase supply. At least one bldg extension, added outdoor security lights, etc. Each extension of the installation was facilitated via its own CU but all radial spurs from the main supply. I guess ‘someone’ assumed not everything would be on simultaneously.
Caterers were in for an event with a few extra loads.
A parishioner put their hands under a drier in the loo causing the main supply fuse to blow.
@cybergibbons@infosec.exchange @guardeddon@qoto.org @wishy@tooter.wishy.co.uk "Never trust a tea urn" is a good rule for life. Caterers will do all the dubious overloading that the stage lighting people will attempt, without any of the electrical awareness. (Bonus points for the presence of both at the same venue, so the tea urn tips it over the limit.)
@guardeddon @wishy I remember helping setup a marquee for an event at a church. There were two tea urns inside, two outside.
Looked at the fuse board. Old fuse wire jobby.
Told them to limit the urns and slow down the tea!