Does a cable have to have a CPC?

[Gringoking88]

Hi all,

Hope you are all well and all is good.

I'm having to install an EV charger tomorrow on a 3 phase TN C S earthing system, however, I need to TT just the charger and am going to put in a spike and run the earth only to charger keeping separate from the main supply fuse board. My question is, can I use a 4 core hi tuff cable from the main board to the charger and not have a cpc in it as it won't be used for the earthing anyway the supply will be RCD via type A rcbos, or do I have to use a 5 core cable with a CPC?

Thanks in advance and appologies if this is obvious and I'm just missing it.

M

 

[loz2754]

Hi.
The regulations state that every point in a circuit needs to have a CPC that is connected to the main earth at the origin. In this case, to the earth rod. The CPC does not have to be contained within the cable itself necessarily, and if a separate CPC is to be run, it either has to be mechanically protected, or have a minimum csa of 4mm².
Obviously it's a bit last minute now, but you would probably be better using a 5 core cable.

 

[Dustydazzler]

i guess all depends if it’s cheaper to run a smaller supply cable with seperate earth cable or a bigger cable with the requisite number of cores

 

[littlespark]

I would say the cable itself needs it. A cpc is a circuit protective conductor and the cable is part of the circuit.

what if they get a different charger in the future and at that time it needs a cpc

 

[Gavin John Hyde]

Hi all,

Hope you are all well and all is good.

I'm having to install an EV charger tomorrow on a 3 phase TN C S earthing system, however, I need to TT just the charger and am going to put in a spike and run the earth only to charger keeping separate from the main supply fuse board. My question is, can I use a 4 core hi tuff cable from the main board to the charger and not have a cpc in it as it won't be used for the earthing anyway the supply will be RCD via type A rcbos, or do I have to use a 5 core cable with a CPC?

Thanks in advance and appologies if this is obvious and I'm just missing it.

M

TT'ing the charger whilst required for a.lot of chargers can be the most obvious option.Pen fault detection units are they way to go. Good chargers have it built in.
For sake of an extra core in the cable run a cpc from the origin. On a 20m run it will add less.than £20 to cost and alleviate the issue.
I note you are using hituff - swa could be better as you have the armour to use as a cpc... Swa is often cheaper too as its more commonly stocked.
With EV installs ot amazes me how many people try to do the bare minimum to install it. Spend just a little bit more time and money and the install is so much better.

 

[Gringoking88]

Hi.
The regulations state that every point in a circuit needs to have a CPC that is connected to the main earth at the origin. In this case, to the earth rod. The CPC does not have to be contained within the cable itself necessarily, and if a separate CPC is to be run, it either has to be mechanically protected, or have a minimum csa of 4mm².
Obviously it's a bit last minute now, but you would probably be better using a 5 core cable.

Hi,

Thanks for the advice appreciated, think I will run it in 5 core swa and run the earth back to the board keeping it separate from the pme earthing system.

 

[Gringoking88]

TT'ing the charger whilst required for a.lot of chargers can be the most obvious option.Pen fault detection units are they way to go. Good chargers have it built in.
For sake of an extra core in the cable run a cpc from the origin. On a 20m run it will add less.than £20 to cost and alleviate the issue.
I note you are using hituff - swa could be better as you have the armour to use as a cpc... Swa is often cheaper too as its more commonly stocked.
With EV installs ot amazes me how many people try to do the bare minimum to install it. Spend just a little bit more time and money and the install is so much better.

Hi,

Normally we use Garo units as PEN fault detection units, however, this is a 3 phase installation so a rod is much cheaper in this scenario. Agree with the cost difference in cable, I will go with 5 core SWA. It wasnt so much the money, it was more about the efficancy of the installation not to mention the client does not want a massive 3 phase PEN fault detection unit.

Appreicate the advise,

 

[telectrix]

Hi,

Thanks for the advice appreciated, think I will run it in 5 core swa and run the earth back to the board keeping it separate from the pme earthing system.

if you are using SWA you can use 4 core, armout as cpc for the SWA but isolated from the TT charger installation.

 

[DefyG]

run the earth back to the board keeping it separate from the pme earthing system.

The cable earth should be connected to the pme system but not the TT arrangement. It should be kept separate at the load end not the supply end.