Matt-e open PEN

[marcuswareham]

Hello

Hope your staying safe and well with Covid-19

I am wondering if someone could confirm this for me.

I have seen these Single Phase EV Voltage Monitoring and Protection Unit - https://www.cef.co.uk/catalogue/products/4873097-single-phase-voltage-monitoring-and-protection-unit

The Matt-e EV charging box to protect against PEN conductor fault

I understand the way this works is by monitoring the voltage between L - N and if the voltage is within the range of 207 V - 253 V then it will close the contacts on the contractor, if the voltage is outside of this range the contractor will be open disconnecting supply L, N & PE

In accordance with 18th amendment 1
Section 722.411.4.1. point (iv)

My question is as far as I understand it the same results can be achieved with a voltage monitoring relay and a contractor like so:
View: https://www.amazon.co.uk/gp/product/B07QDKSDPL/ref=ox_sc_act_title_2?smid=A249EEO40WNRMY&psc=1


and

Techna KTEC25-11-240 Contactor Ktec25 240VAC Coil

Techna - KTEC25-11-240 - Techna KTEC25-11-240 Contactor Ktec25 240VAC Coil - <P>This Techna Ktec contactor allows switching of high current/power using low

www.rapidonline.com

So the L - N goes through the voltage monitoring relay and that is set to close the contacts of the contractor if the voltage is between 207 V - 253 V. and the three poles of the contractor are L, N & PE

This seems like a cheaper way to achieve the same thing, also with the benefits of being able to but it in your own enclosure (weather that be the main C/U or a small sub C/U)

Would this still be within the regulations, as you have used multiple products rather than one product for the EV outlet

Have a good day

Many Thanks

Marcus

 

[marcuswareham]

Also, if someone was installing at Matt-e device how would you test it.

Like testing an RCD with a MFT for disconnection times.

I guess you would need a variable transformer to simulate under and over voltage, but not sure how you would measure disconnection time.

 

[snowhead]

You wouldn't be able to test it unless it had a built in test function, you'd have to rely on the extensive testing for reliability that the makers will have done.

That would be the problem wtih using separate components, you would have needed extensive testing to prove they reliably disconnect when required.

 

[Gavin John Hyde]

Having fitted a few of these now on ev charger installs in my area, I am not fully comfortable with them, but its all we got and the manufacturer says it is compliant, as do the regs. So am covered in that regards verses using a rod that if it can even be installed gives a good reading today but the ground conditions around here can make them fluctuate significantly in warmer weather compared to after rain.
There is no way to test them from what I am aware, did read some where something about putting a variable resistor on the conductors but this was done on a youtube video to vary the voltage and current etc..
This is the downside to them. a bit like AFDD and SPDS there is very little in the way of being able to test them. over time I think this will change.. but as more and more chargers incorporate this technology in the actual charger the open pen device from matt:e may become obsolete.
I have however heard of somebody using one to export PME to a metal shed! enough said...

 

[marcuswareham]

You wouldn't be able to test it unless it had a built in test function, you'd have to rely on the extensive testing for reliability that the makers will have done.

That would be the problem wtih using separate components, you would have needed extensive testing to prove they reliably disconnect when required.

Ok I see,

If you had a way to test it, would this still comply then
[automerge]1586697954[/automerge]

Having fitted a few of these now on ev charger installs in my area, I am not fully comfortable with them, but its all we got and the manufacturer says it is compliant, as do the regs. So am covered in that regards verses using a rod that if it can even be installed gives a good reading today but the ground conditions around here can make them fluctuate significantly in warmer weather compared to after rain.
There is no way to test them from what I am aware, did read some where something about putting a variable resistor on the conductors but this was done on a youtube video to vary the voltage and current etc..
This is the downside to them. a bit like AFDD and SPDS there is very little in the way of being able to test them. over time I think this will change.. but as more and more chargers incorporate this technology in the actual charger the open pen device from matt:e may become obsolete.
I have however heard of somebody using one to export PME to a metal shed! enough said...

Yes indeed, testing is an issue

Funny you mention about a metal shed, I work as an electrician for temporary live events. We often have issues with PME as we often need to power tour busses and outside broadcast trucks outside.

For OB trucks there is a bit in BS7909 which says PME earthing can be used provided the OB truck is under constant skilled supervision (which is how it is normally done now as if you make the OB truck TT or isolate it often you bridge the earths with signal cables going into the building)

For tour bus it is often ignored or on a TT or IT supply, TT is not always practical as its only temporary and often cannot get permission for rods. and IT adds considerable cost when you need a 32A 3P for each tour bus.

I looked at the Matt-e devices or similar as an alternative, but am still not sure yet

Thanks Marcus
[automerge]1586697954[/automerge]

Having fitted a few of these now on ev charger installs in my area, I am not fully comfortable with them, but its all we got and the manufacturer says it is compliant, as do the regs. So am covered in that regards verses using a rod that if it can even be installed gives a good reading today but the ground conditions around here can make them fluctuate significantly in warmer weather compared to after rain.
There is no way to test them from what I am aware, did read some where something about putting a variable resistor on the conductors but this was done on a youtube video to vary the voltage and current etc..
This is the downside to them. a bit like AFDD and SPDS there is very little in the way of being able to test them. over time I think this will change.. but as more and more chargers incorporate this technology in the actual charger the open pen device from matt:e may become obsolete.
I have however heard of somebody using one to export PME to a metal shed! enough said...

Yes indeed, testing is an issue

Funny you mention about a metal shed, I work as an electrician for temporary live events. We often have issues with PME as we often need to power tour busses and outside broadcast trucks outside.

For OB trucks there is a bit in BS7909 which says PME earthing can be used provided the OB truck is under constant skilled supervision (which is how it is normally done now as if you make the OB truck TT or isolate it often you bridge the earths with signal cables going into the building)

For tour bus it is often ignored or on a TT or IT supply, TT is not always practical as its only temporary and often cannot get permission for rods. and IT adds considerable cost when you need a 32A 3P for each tour bus.

I looked at the Matt-e devices or similar as an alternative, but am still not sure yet

Thanks Marcus