Innovation Or Just Plain Stupid

[David006]

This is for our venerable sparkies:

We have a remote (300m) well and pump that is controlled by manual switch up at the tanks next to house.

The switch is wired in the live of course and has a safety-cut.

I want to put some lighting near the well.

Rather than run additional cable I thought it might be possible to switch the neutral thereby having a live at the pump plug socket.

Install a local ground rod and voila, power to the lighting via the plug outlets...

I think it should work but wondering if there is something I have not thought about

The electrical system is MEN

edit: Lighting will be on an auto LS switch...

Edited March 2, 2012 by David006

[Crossy]

Where is the neutral coming from for your lights?

EDIT Are you thinking of using the local ground rod as a neutral i.e. a system called SWER (Single Wire Earth Return)?

SWER is normally found in the HV side of supply transformers and is used to supply remote, low power systems. It uses a single supply wire with the return current passing via the mass of the earth. I've never seen it used on the LV side of a system, it would certainly not be permitted in the UK and I suspect also Oz.

It may work, but you will have issues with the RCD tripping if you have more than about 3 Watts of lighting, and having a switched neutral really is a no-no.

Why not run a second switched live for the lighting, you can use the existing neutral as the return path as the additional load from the lights should be small compared with the pump current. The lights may dim when the pump starts but your RCD will still be effective and the whole system will be safe.

A thought, how is your pump grounded at present if you intend installing an earth stake at the pump house?

[David006]

Where is the neutral coming from for your lights?

EDIT Are you thinking of using the local ground rod as a neutral i.e. a system called SWER (Single Wire Earth Return)?

SWER is normally found in the HV side of supply transformers and is used to supply remote, low power systems. It uses a single supply wire with the return current passing via the mass of the earth. I've never seen it used on the LV side of a system, it would certainly not be permitted in the UK and I suspect also Oz.

It may work, but you will have issues with the RCD tripping if you have more than about 3 Watts of lighting, and having a switched neutral really is a no-no.

Why not run a second switched live for the lighting, you can use the existing neutral as the return path as the additional load from the lights should be small compared with the pump current. The lights may dim when the pump starts but your RCD will still be effective and the whole system will be safe.

A thought, how is your pump grounded at present if you intend installing an earth stake at the pump house?

no worries thanks Crossie: I was not thinking as to what was allowed or...know NZ still as some network based on single live and earth return.

My question is really are there any dangers associated or..already have nuisance trips of GFI about every few months..not an issue really.

Think I will do a "suck it and see".if it don't work or gives me problems well that's fine lots of time here in LOS.....if I am gonna run a new wire (zap strapped to pipe through bush and undergrowth) I would run another triplex cable and done with it.

thx again

rgds

david

[bankruatsteve]

Maybe check out low voltage (battery) lighting? I haven't found anything useful in LOS for that in previous quests, but perhaps better these days?

[David006]

Maybe check out low voltage (battery) lighting? I haven't found anything useful in LOS for that in previous quests, but perhaps better these days?

yeah thanks, did think that through too but figure another 50++ baht a month on the electric bill is a better deal considering the initial investment,amortization, ongoing mtce of decent solar/batteries/lighting...maybe in another few years.. currently have half a dozen Thai style 30W flouros on our power poles beside our road on a light sensitive switch...costing about 300 baht a month.

Wonder when we will see 240v LED plug and play tubes and globes ...maybe the effective equivalent wattage vs consumption should be a great improvement?