[goldtop]

(I've started this thread here as it seems the most relevant place. It comes from a few postings I've made in other people's topics and is a sort of fresh start, now that I've learned a few things from SEVers. Thanks all.)

Starting from the beginning, this is the three-phase supply I have:

I had planned to have a 22kW charger (mostly for future-proofing as I will be leasing an 7kW-AC charging Ioniq for two years). The complications come from being unable to add an earth electrode by the charge point location (for a TT island). The front of the unit looks like this:

As you can see, the only location in on the brick pillar between the two doors. That's perfect for charging a car in either of the allocated spaces, but the incoming gas supply and other services (telephone, water in and drainage out) all run somewhere along and in front of the building.

So, thanks to Mike for posting about the other options:

That's a 3 phase TN supply.

You'll likely need either:

• To tt island each EVSE and manage sim contact risks manually.
• A 3 phase upstram protection device, e.g. Matt:e O-PEN.
• an EVSE that works under indent (iii) or (v), e.g. myenergi Zappi or Indra Smart PRO.

So I'm now looking at those second and third options.

Option 2: As I understand it, the Matt-e is a bigger connection box at the incoming supply, handles the PEN-loss issue for a 3-phase supply (not just a single phase) and its 3-phase output would run to the front wall and then could be a 'dumb' charge point with Type 2 outlet. The car will have the charging schedule smarts, and I would not be using an OLEV grant because that requires a smart charge point (like Zappi, Indra, EVline). For this I would need a competent/qualified electrician - not an OLEV-compliant installer.

Option 3: Quotes for the full install (all 22kW Zappi) are £1200-1500. The Indra seems to be 7kW only. There's also the EVline 300 for 22kW and with their 'Safevolt' PEN-loss protection. Still researching that one.

I'm tempted by Option 2 at the moment. Any reality checks?

(There is the question about what sorts of protection devices are required in the 'dumb box'. I've got to wise up on that.)

 

[freddym]

There is another option:

Mount up / Install a Virdian EVSE aka charger, 3 phase type 2 socket to your front wall.

Run your 3 phase cables back to your supply (with full size neutral of course).

Terminate and connect L1 and neutral at both ends. Make safe L2 and L3 at both ends.

Configure the protocol controller 2 as to have loss of neutral protection and 6mA DC. Job done.

Note, this will be very cost effective.

You will get excellent backup from EcoHarmony aka Viridian

have a read here EVSE+Protocol+Controller+2.0+(EPC+2.0)+Manual+-+Iss+1.1.pdf (squarespace.com)

 

[goldtop]

^ Aha. I had the Viridian widget bookmarked earlier, but had deleted it after reading:

"Full PEN Loss detection functionality in the EPC 2.0 has been designed in accordance with UK specifications (BS 7671: 2018 amendment 1, 722.411.4.1 (iv) and (v)) for single phase charge points only*."

I had taken that to mean that the PEN-loss sensor of the Viridian was not applicable to 3-phase charge points. If I have the wrong end of the stick, that would be good, as I was interested in the Viridian EPC after reading HandyAndy's Rolec update.

A more-informed reading makes this section more relevant to my situation:

"*If the PEN Loss CT is still connected and PEN Loss is enabled, the device will still open the contactors and isolate the charge point socket for the 3 phase charge points (meeting paragraph (v) of the above specification), however full PEN Loss detection has been designed to meet both paragraphs (iv) and (v) of the above specification and not all live conductors are being measured in a 3 phase charge point by the EPC 2.0."

But wouldn't I be drawing all 96A from one phase, with your plan? Bit marginal?

 

[HandyAndy]

Viridian PEN-loss protection will work, but only on one phase. So you'd have a 7kW charger, as I see it. "Make safe L2 and L3 at both ends" I assume means these are not connected up.
Nothing stopping you having 3 EVSEs, each of 7kW, on the 3 separate phases, each with its own Viridian + PEN-loss protection & 6mA DC protection as far as I can see.

 

[freddym]

As HandyAndy has surmised, you would be meeting the anticipated single phase 32A charging requirements of your leased car for the next 2 years, AT A LOW INITIAL UPFRONT COST.

The EVSE and the cabling would be in place for an upgrade to 3 phase should that be required in the future.

Since you have a three phase supply to the commercial unit, installation of a total installation loss of neutral device would stop you blowing up lighting, computers, office equipment etc and might be worth considering IN THE FUTURE SHOULD IT BE NEEDED. Not that incredibly difficult.

Your electrician would of course need to look at the loading across the 3 phases, and how this varies.

This in a lot of ways is much easier than the normal issues with single phase supplies.

Cheers

 

[goldtop]

Gotcha. I had the impression that it was 'A Bad Idea' to add a charge point to a single phase of a 3-phase supply unless all of the phases had PEN-loss protection.

So, the lowest-cost approach for now with some future-proofing:

1. add heavy-duty three-phase wiring between supply and EV charge point now
2. ignore two of the LIVEs (make safe)
3. install Viridian EPC in a dumb 7kW AC charge point
4. use its PEN-loss protection
5. add 6mA DC protection
6. use to charge the Ioniq during the next 2 years
7. put up with approx 6hr recharge (no biggie)
8. revisit the charge point at the next car change

In essence, then, the charge point would be rather like HandyAndy's upgraded ROLEC, after all.

 

[HandyAndy]

Yup. Or simply buy a Viridian in the first place. Nice solid metal box apparently, and good quality components throughout. If you ask them, they might put a 3-phase Contactor and 3-Phase socket/cable in at the same time, even though 2 of these won't be used for a while. You never know, they might come up with a 3-phase version of their own PEN-loss device in the next year or so that you could then simply slot straight in, and wire up L2 & L3 for instant upgrade!

 

[goldtop]

Started looking into the cabling (least sexy bit of the whole thing, but rather important to specify correctly). I suppose a trained spark know these numbers by heart, but I'm just getting to grips. So I used this useful doc: https://www.marlec.co.uk/wp-content/uploads/2014/03/H07RNF1.pdf

From that, three-phase 5-core: 4mm seems marginal for 32A, and therefore 6mm seems more sensible (47A). Part of the run will be in a ceiling void where there will be little-to-nothing in terms of ventilation/passive cooling. This spec covers the outdoor part of the run which needs to be weather-resistant (but not armoured, as I understand it, as it's not being buried or chased into the wall at any point).

So this looks like the type of cable needed: 6mm x 5 Core H07RN-F Cable - Price per metre, cut to length

That's 10m + 2m (for my measuring tolerance!) = £53 (approx).

One question: is over-specifying the wire - say, going to 10mm for 64A rating - worth it for future-proofing? I can't think of any likely AC charging developments which would make the extra bulk and awkward cabling work worth the effort and hassle.

 

[goldtop]

Three-phase PEN-loss device bought. Mike had mentioned these earlier, and one came up:

The extra device ('extra' meaning that it is one I hadn't seen on other installs) is for phase loss protection. I don't know how often that happens, but given that this is a workplace on an industrial estate, it's perhaps more likely to happen here.

I did read that some reviews thought the Matt:e was hummy/noisy, but that doesn't matter for this location.

This will go on the wall by the distribution board (shown above). The working plan is then to follow Freddy's advice and connect via the above-mentioned wire to a Viridian EPC-based box on the outside wall.

Q1: should I get the electrician to treat this as a consumer unit and add Henley Blocks?

Q2: are there any other modules I could or should put in there - e.g. surge protection? Looks like there's space for 4 module-widths.

Q3: it's 63A rated. Should I swap to 40A? I'm thinking of the relationship: Ib < = In < = Iz

 

[Aragorn]

I dont think it appears to contain any over current protection, so really you'd want to feed it from an RCBO in your CU as normal.

H07 is fine (though will require bootlace ferrules) though you might be better off with NYY-J.

Did the o-pen come with installation instructions?

 

[freddym]

I dont think it appears to contain any over current protection, so really you'd want to feed it from an RCBO in your CU as normal.

H07 is fine (though will require bootlace ferrules) though you might be better off with NYY-J.

Did the o-pen come with installation instructions?

Check with your Sparky as to whether RCBOs are available for your board. Even if they are, they may not be advisable due to discrimination issues. You may end up with MCBs. This really needs to be designed as a system with knowledge of the type of RCD going into the EVSE.

 

[goldtop]

I dont think it appears to contain any over current protection, so really you'd want to feed it from an RCBO in your CU as normal.

H07 is fine (though will require bootlace ferrules) though you might be better off with NYY-J.

Did the o-pen come with installation instructions?

Excellent input - thanks.

1 - Yes. I don't think the internal layout suits an internal RCBO.

2 - aha. I've just watched an eFixx video on ferrules, but the solid-core NYY-J would make that unnecessary (although it would be the electrician doing the hook-up, not me, and he'd have the right skills and gear for ferrules).

3 - None that's very specific as far as I could see. There is just the manual on Matt-e's website (which appears to be down at the moment), but I've already saved the PDFs.

 

[goldtop]

Check with your Sparky as to whether RCBOs are available for your board. Even if they are, they may not be advisable due to discrimination issues. You may end up with MCBs. This really needs to be designed as a system with knowledge of the type of RCD going into the EVSE.

Will do. I'd previously bookmarked the GARO version: 32A RCBO 3P+N Type A Char C 30mA (Garo)

That notes: "A suitable rated RCBO/RCD device may also be required in the final circuit to provide the correct level of protection whilst avoiding unnecessary tripping."

 

[freddym]

Will do. I'd previously bookmarked the GARO version: 32A RCBO 3P+N Type A Char C 30mA (Garo)

That notes: "A suitable rated RCBO/RCD device may also be required in the final circuit to provide the correct level of protection whilst avoiding unnecessary tripping."

Is that a Garo distribution board you have?

 

[Aragorn]

The board already has at least one RCBO in it, i can see the test button (infact i think there are three). So they are clearly available. That style of 3 phase DB should have no issues with RCBO's. I'm not sure what discrimination issues freddy expects, but the main switch is clearly not RCD protected so RCBO's on the final circuits is the way to go. Its also fairly typical in a commercial installation to do things that way.

The RCBO's need to match the board you have, i cant make out a brand name, but you cant just go buying any old RCBO.

I wouldnt assume your spark will have ferrules. They arent super common outside of industrial or electronics environments. A typical sparky will tend to use "solid" core cables which dont need it. NYY-J is often cheaper than H07 too.

 

[HandyAndy]

I'd be hesitant about using any overcurrent device labelled 32A. My first ever 32A charge (Ioniq 38 kWh) on my EVSE went fine for about 20 mins, then the MCB/RCD tripped & cut the whole thing. After some research & monitoring, I found my car was drawing 31.5A. The 32A device derates the trip current as the temperature rises, and mine in the small mini-CU was getting to just over 30C, and clearly the current was derating a tiny bit, until the trip-current reduced to 31.4A and bingo, it did it's job.

I replaced with a 40A one and it's been fine since.

 

[Aragorn]

They are generally rated to do nothing at all until about 1.1x their rating. So you'd expect a 32A MCB to flow 34-35A indefinitely.

 

[freddym]

The board already has at least one RCBO in it, i can see the test button (infact i think there are three). So they are clearly available. That style of 3 phase DB should have no issues with RCBO's. I'm not sure what discrimination issues freddy expects, but the main switch is clearly not RCD protected so RCBO's on the final circuits is the way to go. Its also fairly typical in a commercial installation to do things that way.

The RCBO's need to match the board you have, i cant make out a brand name, but you cant just go buying any old RCBO.

I wouldnt assume your spark will have ferrules. They arent super common outside of industrial or electronics environments. A typical sparky will tend to use "solid" core cables which dont need it. NYY-J is often cheaper than H07 too.

Hi Aragon and OP, yes agree final circuit protection is the way to go. That's with the RCD function in the Distribution Board ( consumer unit is a misnomer). Since we don't know what EVSE will be fitted, there is a problem with discrimination if RCDs are also included in the EVSE. So OP needs a spark on the ground that can look at the entire proposed system, as well as one that will sign it off. Don't forget the DC leakage detection/ trip function too.

 

[freddym]

Hi Aragon and OP, yes agree final circuit protection is the way to go. That's with the RCD function in the Distribution Board ( consumer unit is a misnomer). Since we don't know what EVSE will be fitted, there is a problem with discrimination if RCDs are also included in the EVSE. So OP needs a spark on the ground that can look at the entire proposed system, as well as one that will sign it off. Don't forget the DC leakage detection/ trip function too.

PS, not sure what that GARO unit is going to be used for!

 

[freddym]

They are generally rated to do nothing at all until about 1.1x their rating. So you'd expect a 32A MCB to flow 34-35A indefinitely.

Poor practise😦