EV Charger

[Tomosmorris94]

I have just installed my first EV Charger yesterday. I have installed using a 6mm twin from the non RCD side of the consumer unit on a 32a type b MCB. The length of run is around 5 metres and is contained in 20mm round conduit.

The charger I have fitted is a Rolec with a built in type A 30mA RCBO. I have installed an earth rod below the charger as I was told EV chargers can rely on the earth of a TNC-S system.

Upon testing j had a reading of 347 ohms on my Rod and 24.8ms on my RCD. my question is, would this be sufficient as it is protected by a 30mA RCBO therefore the maximum reading permittable is 1667ohms or am I wrong and does it have to be below 200ohms?? 50volts (touch voltage / 0.03 = 1666.66.

Thanks guys! Go easy, this is my first post!

 

[hasel5]

Needs to be under 200 ohms mate and if guy has a Zoe under 100 ohms

 

[Tomosmorris94]

Needs to be under 200 ohms mate and if guy has a Zoe under 100 ohms

He has an i3. Would you suggest banging another rod in then??

 

[hasel5]

You will need to get it below 200 at least

 

[pc1966]

He has an i3. Would you suggest banging another rod in then??

Is it the sort of rod that you can use a joining piece and add another length to it to bang in?

Generally a deeper rod is more stable against frost or drought changes than the equivalent of two shallow ones. That is the reason for the 200 ohms mentioned in 18th Table 41.5 (also citing 542.2.4) even though a 30mA RCD is theoretically OK with 1667 ohms.

 

[Tomosmorris94]

Is it the sort of rod that you can use a joining piece and add another length to it to bang in?

Generally a deeper rod is more stable against frost or drought changes than the equivalent of two shallow ones. That is the reason for the 200 ohms mentioned in 18th Table 41.5 (also citing 542.2.4) even though a 30mA RCD is theoretically OK with 1667 ohms.

Hi mate. No it is not one you can add an extension onto it ?. I read up in the regs regarding the 1667ohms if protected by a 30ma RCD. So would this reading of 347ohms be sufficient??

 

[mattg4321]

I wouldn’t be happy with it personally. Get a couple of 5/8 rods that you can join and whack them in. If that doesn’t get it significantly lower then go with a couple more 8 feet away.

 

[jackhammerJIM]

I have just installed my first EV Charger yesterday. I have installed using a 6mm twin from the non RCD side of the consumer unit on a 32a type b MCB. The length of run is around 5 metres and is contained in 20mm round conduit.

The charger I have fitted is a Rolec with a built in type A 30mA RCBO. I have installed an earth rod below the charger as I was told EV chargers can rely on the earth of a TNC-S system.

Upon testing j had a reading of 347 ohms on my Rod and 24.8ms on my RCD. my question is, would this be sufficient as it is protected by a 30mA RCBO therefore the maximum reading permittable is 1667ohms or am I wrong and does it have to be below 200ohms?? 50volts (touch voltage / 0.03 = 1666.66.

Thanks guys! Go easy, this is my first post!

I would not be happy with that reading . You should be attempting to get the reading as low as possible within a budget . This week we installed a similar setup with a 5/8s rod achieving 40 ohms . Last week we used 2 and got down to 20 ohms . Considering a rod and clamp is around £15 its hardly breaking the bank .

 

[Tomosmorris94]

I would not be happy with that reading . You should be attempting to get the reading as low as possible within a budget . This week we installed a similar setup with a 5/8s rod achieving 40 ohms . Last week we used 2 and got down to 20 ohms . Considering a rod and clamp is around £15 its hardly breaking the bank .

Cheers mate. Not that it's breaking the bank, just that it's in a hell of an awkward location. Gas and electric income within a couple of foot as well as 3 drains ?? I think I will just bang another rod in to be on the safe side but just hoping I don't hit anything!

 

[pc1966]

If you already have a rod in and know that particular place is safe, then put in a longer one in its place, maybe using a joining section so each section is manageable.

When I recently put in some 2m x M16 threaded stainless rod for earthing I used a 1m long SDS drill to get down the 1st metre before driving/screwing the rods in - that might help you get a bit deeper with the 5/8" = 16mm style of jointed rod.

If you put in a 2nd rod very close it will make little difference to the Ra value, you really want to be a rod's length away, or ideally two rod's length or more if paralleling rods.

 

[jackhammerJIM]

Cheers mate. Not that it's breaking the bank, just that it's in a hell of an awkward location. Gas and electric income within a couple of foot as well as 3 drains ?? I think I will just bang another rod in to be on the safe side but just hoping I don't hit anything!

Next time you look at an EV job if rodding is going to be a nightmare order a PEN fault relay and you wont have to use an earth rod .

 

[Tomosmorris94]

Next time you look at an EV job if rodding is going to be a nightmare order a PEN fault relay and you wont have to use an earth rod .

Cheers mate. Where would you get a pen fault relay from, how much are they and how would you install them?

 

[pc1966]

Cheers mate. Where would you get a pen fault relay from, how much are they and how would you install them?

Here are some examples:
https://www.cef.co.uk/catalogue/cat...]=wh_321347&sort=price_inclusive_vat.sort_asc
You might find it cheaper elsewhere like your local wholesaler, of course...

 

[hasel5]

Another option is fit a unit with a pen device fitted

 

[jackhammerJIM]

Cheers mate. Where would you get a pen fault relay from, how much are they and how would you install them?

Rolec make one i think they are around £110 plus vat . Comes in a 4 way db with 40amp rcbo included .

Also the zappi chargers have them inbuilt as standard and im sure a few other makes also .