Cottage supplied by 16mm SWA 300+ yards! Trying to resolve a high Ze reading

[RobertLow]

It is certainly undersized by some way but they are not necessarily working to the requirements like us. I would question it and see their response.

This cable was not run by the electricity supplier. It was run by a previous electrician who did work on the farm and this cable was reconnected into the new mains box when the supplier brought in new overheads. So unfortunately it isn't them who are to blame, but some old retired spark somewhere around here!

 

[westward10]

Got you. That cable is certainly undersized with regard to volt drop which isn't necessarily a concern with an EICR unless it is giving issues but the armour is, personally I Code 2 these instances as it is inadequate to support main protective bonding.

 

[Flanders]

Agree with westwood That SWA need terminating correctly. I would give a code 2 for that. I would also code 2 those exposed single insulated cores of the SWA . To fix the HI zs though you would have to down rate the main fuses, fit a main upfront 300ma RCD at the DNOs supply box Or run in a new cable.

 

[Greenarmy]

The two supplies are also sharing the same neutral .

 

[mainline]

Hi, isn't the 1667 ohms reading only for Type S RCD's? in page 70 of the regs i see that value in a table. regarding S type?

type S rcd = time delay
The 1667 ohm is the maximum earth loop for a 30ma rcd

 

[marconi]

Now

Hi, while carrying out an EICR at a farm cottage on Friday i came up against a problem early on. Whilst measuring the Ze the reading i obtained was 0.97 Ohms and 27Amps Pfc.
CH]

Assuming Uo of 230V then calculated PFC is Uo/Ze = 230/0.97 = 237A not 27A, a factor 10 different. Is 27A a typo and you meant to write 237A?

 

[marconi]

The two supplies are also sharing the same neutral .

For a split phase or two of three phase supply the neutral never carries a residual current of more than that of the highest line's current.

Is the remark you made directed at the fact that the shared neutral conductor in the cable to the cottages is fed by two switched neutrals?

 

[ukiri]

If the shared neutral is lost ,won`t you be getting 400v across both cottages? 2 phase US style but double the Voltage.