Need a sparky's opinion on connecting a simple 1P 32A home charger

[4myr]

EV charger
I want to install a single phase 32A home charger for an EV.

Preferably one which the current can be varied, so the idea is I can charge for free during sunny hours from my grid-tied solar by lowering the current [ 8A-10A-13A-16A ].

Later I can automate the current [A] setting in Homekit to dynamically adapt to the actual solar production. 

I had this Feyree charger [ https://www.aliexpress.com/item/1005005875505790.html ] in mind.
I am looking for one which is IEC 61851-1 compliant.
It is not explicitly stated to be certified. It says: “Control box meet IEC 61851 control principle”. 

 

 

This one is also an option [ https://www.aliexpress.com/item/1005007741078236.html ].
It has no mention of IEC 61851, but it has RCD type B protection built in.

 

 

Q1: Which one to take or do I need to look for another charger that is explicitly 61851-1 certified to be on the safe side?
 

 

PEA meter and smart invoice
I am selling my excess electricity to PEA, so they fitted a digital 30(100)A meter.

This meter registers off peak consumption separately as seen on my PEA “smart invoice”.
However the invoice clubs all consumption into a single rate of 3.2484 baht/kwh.

Currently I have a consumption below 100 kwh per month. Also service charge is low at 24.62 baht.

 

Q2: If I start to consume 140 kwh per month extra for my EV and charge it during off peak hours, what do I need to do to get from PEA a lower off peak tariff?

 

 

Main consumer unit - integrated MCB/RCBO
The main breaker is 63A, it will be sufficient for my additional 32A charger.
However the MCB is an integrated unit with the RCBO, called CMT-2. See attached picture.

 

 

Link: https://www.thaiwatsadu.com/en/product/เมนเบรกเกอร์-RCBO-CT-ELECTRIC-รุ่น-CTM2-63c-สีดำ-60264396

 

What is my gripe? At the EV charger side there will be a RCD type B breaker.
All the connections in the main CU are connected to the integrated RCBO.
I think this will not work well, having RCBO and RCD on the same EV charger circuit.
So I want to route a separate EV breaker from the main MCB without the RCBO. 

 

Q3: is there a safe way possible with the existing CMT-2 to break open the bottom cover and route a cable from the MCB without RCBO. 
Or do I need to replace the CMT-2 unit or even the complete CU. The brand is Gsafe and the CU is 8 years old? 

Is there another simple route possible, as what I've read PEA does not allow a second line anymore for EV chargers?

 

 

Solar DC cable interference
The easiest way to route the new 15m 32A EV cable is to share a 1 meter conduit with my solar DC cables up to the attic floor.

Peak capacity of DC is 4500Wp.

 

Q4: Do I still need to avoid or minimize EMI interference from the dc cables, as Thailand requires onboard EV chargers to be EMC compliant?
The home charger I have in mind does not mention any EMC compliance. If so, how to avoid/minimize?

 

 

EV breaker box / MCB rating
The standard configuration I read for the EV breaker box is a MCB for overcurrent protection of the AC cable.

The recommended rating in Thai I read is 40A. Also recommended AC cable size is 10 mm2. I agree with oversizing the cable. I
want to trip the MCB asap on the lowest overcurrent possible.
Because of the bimetal the time that it will trip can take hours also depending on current and ambient temperature. 

 

Q5: Is MCB rating of 32A not better to spare the cable than the recommended 40A? 

 

 

EV breaker box / RCD type B
Some EV chargers mention a built-in RCD type B with leak current protection of AC 30mA + DC 6mA.
Thai papers I read also recommends a rating of 40A for the RCD.

 

Q6: Is it from Thai regulation required to still have an external RCD breaker installed, if the home charger already has a rcd type b?
If so, will the circuit work properly with 2 RCD breakers in series?

Q7: If the MCB is rated 32A, do I need to match the rating of the RCD to 32A also?