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Discussion Starter · #62 ·
Another thing worth mentioning, is that your RCD is a typeA RCD. It needs to be changed asap to a TypeB RCD...
There's a 40A RCBO inside the EVSE unit downstream from this mini CU box; will that do the job?
 

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Discussion Starter · #64 ·
I use a torque screwdriver for all final terminations, 2.5nt.
Just collected a B40 by Hager. Acc to the shop, this make requires an exceptionally high torque compared to other makes. It's 3.2 Nm ! So that's what it'll get, as soon as I can get a Draper torque s'driver delivered. Just have to be d*mn tight for a couple of days... :)
 
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Acc to the shop, this make requires an exceptionally high torque compared to other makes. It's 3.2 Nm !
That's not huge. IIRC on my MK CU the main switch screws are 3.5 nm but the breakers are a bit less (2.5 or 3, but I'd have to look it up).
 

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His is AC.
Vehicle converts AC to DC to charge the vehicle. DC creep leakages can occur to ground, and silently kill the TypeA RCD

There's a 40A RCBO inside the EVSE unit downstream from this mini CU box; will that do the job?
Probably, but it is still a good idea to switch over to the TypeB for maximum protection. If you have a neighbor with solar panels installed, even their DC leakage can wreak havoc on TypeA RCDs
 

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Discussion Starter · #70 ·
... but it is still a good idea to switch over to the TypeB for maximum protection. If you have a neighbor with solar panels installed, even their DC leakage can wreak havoc on TypeA RCDs
Yikes! neighbour? What about my own panels ??? :eek: Ok, I'll get me a type B 40.
But, should I have an RCD, or RCBO? Google suggests RCBO = RDC + Switch; presumably the MCB I have is already that switch, so just a plain 'old B40 RCD is what I should have? So much to learn, just as I thought it was all settled ...
 

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Yikes! neighbour? What about my own panels ??? :eek: Ok, I'll get me a type B 40.
But, should I have an RCD, or RCBO? Google suggests RCBO = RDC + Switch; presumably the MCB I have is already that switch, so just a plain 'old B40 RCD is what I should have? So much to learn, just as I thought it was all settled ...
And now we enter a world of confusion because someone, somewhere didn't think when they allocated letters to types ...
  • MCBs come in different flavours (or trip curves) - A, B, C, D, K, Z.
  • RCDs come in AC or 'any' trip sensitivities - A or B.
AFAIK there are NO RCBOs with a B (DC) RCD function and if you Google Type B RCBO you will find a zillion of the B type overload trip curve ... because Murphy made sure that was the commonest type.
You maybe see the problem here with using the same letter series for both systems.

If you want type B RCD then (at present) I think you need to get a separate device, and they are usually 3 or 4 modules wide. (I haven't looked in about 6 months, so that may have changed.) They also tend(ed) to be about £150 a throw.
 

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The most important line from that guide:
"

Type B RCD are intended to be used for loads with three-phase rectifier, such as variable speed drives, PV system, EV charging station and medical equipment.
"

To confuse this even more, RCDs are called GFCIs in Europe :D But thankfully they use the same TypeA/B definition
 

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Type B RCD are intended to be used for loads with three-phase rectifier, such as variable speed drives, PV system, EV charging station and medical equipment.
I noticed that too. It might explain why they seem to be so wide and expensive as the single phase ones are probably just altered 3ph (until demand is enough to produce a line of smaller ones).
 
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