Measuring earth leakage current and live/neutral "escape" current in EV charger?

[Flyback]

Hi,
In a 16Arms EV charger, how do you measure the earth leakage current?
Is its limit 6mA?
Also, how do you measure the difference current between live and neutral.?
(As you know, it should be the same current in live and neutral, but may not be in fault conditions).

Is the difference between live and neutral current allowed to be up to 30mA?

Sorry , but i searched the web, and nowhere tells the difference between the above two fault currents.

 

[rjenkinsgb]

An ELCB.
Those generally use a single current transformer, around _both_ power phases. Exact matched current gives zero output, it only senses any unbalanced current, which must be the leakage.

 

[Flyback]

Thanks, do you know why they measure both earth leakage and live/neutral imbalance in 16Arms EV wall boxes?...using two CT torroids.
Why not just do earth leakage?

 

[Diver300]

Thanks, do you know why they measure both earth leakage and live/neutral imbalance in 16Arms EV wall boxes?...using two CT torroids.
Why not just do earth leakage?

A car is generally insulated from the ground and so earth leakage is a valid thing to read.

It could just be that the manufacturers are being extra careful, for a relatively new and relatively expensive product.

I've seen how vehicle manufacture and service has gone somewhat paranoid about EV safety. It's "high voltage" at 400 V. Special training is needed to work on stuff with "high voltages", sometimes including stuff like the door systems of an EV, with 12 V motors. And if anyone needs to use the vehicle lift, it's powered at 415 V, but it's "low voltage" and vehicle lifts have been around for ages, so they are accepted and used without special precautions about the supply voltage.

 

[KeepItSimpleStupid]

Sometimes it makes sense to look at an early design. e.g. https://media.digikey.com/pdf/Data Sheets/Texas Instruments PDFs/LM1851.pdf

Thanks, do you know why they measure both earth leakage and live/neutral imbalance in 16Arms EV wall boxes?...using two CT torroids.
Why not just do earth leakage?

I'm surprised at you, Where is the earth leakage? You can;t really answer that, can you?
If you measure the imbalance, you know what it is, but you don;t know WHERE it is. The key is where.

One you measure indirectly and measuring earth leakage is impossible. Want to put a probe between your boot and the ground?

You also need to check for a grounded neutral. in the wrong place. You also get reversed polarity.