Unexpected / Strange Voltage

[OldTaffy]

Hi

Been wiring in a Jacuzzi at a customers.

Wired it to a DP Fused connector unit (to isolate), then to switch junction box.
Switch wire goes to a single pole on/off switch outside the bathroom
The Switched live from Junction box goes to Jacuzzi.

I tested it ALL OK. IR test was +299. RCD Fine. Continuity all fine.

After the tests I still had my Megger attached to the Jacuzzi L + N on Voltage scale.
I noticed that the Megger was reading 180V even though the switch outside the bathroom was OFF.

So I checked FCU, Junction Box, Consumer Unit and switch wiring - Couldn't find anything.

Is this an Inducted 'voltage', that will dissipate?
It does disappear if the FCu is turned off.

Also the Switch cable does run along side 3 other cables and the shower cable too for a short while.
Turning off the shower at the pullswitch didn't make the voltage disappear.

Only things I can think of are -
- Inducted Voltage ?
- Faulty Switch ?
- I've wired the Switch and Jacuzzi the wrong way (Pretty sure I've not, but need to test)

Fast answers appreciated as the customer is already a bit miffed over a couple of other unrelated issues

 

[Guest111]

any capacitors attached to the motor?

 

[Octopus]

Turn off the other circuits and retest?

 

[GLENNSPARK]

residue from the IR test?

 

[westmac]

residue from the IR test?

I don't know whether to ask if you're being serious.

 

[GLENNSPARK]

I don't know whether to ask if you're being serious.

no..
like murdoch says...kill all other circuits see if it disappears...

 

[Badged01]

I like the residue theory better, it could have stuck some of the voltage in there permanently ........ sorry being stupid on a Fri morning but 180V does seems to be a high voltage to induce!!

 

[OldTaffy]

no..
like murdoch says...kill all other circuits see if it disappears...

And if it doesn't disappear? Am I looking at the switch.

I thought 180v was rather large to induce!!!

 

[Octopus]

Whats a switch junction box?

 

[OldTaffy]

Whats a switch junction box?

A junction box wired like a ceiling rose, so when switch o/s bathroom is flicked the switched live energises the Jacuzzi

 

[Octopus]

A junction box wired like a ceiling rose, so when switch o/s bathroom is flicked the switched live energises the Jacuzzi

So its a junction box with 4 or more terminals!

 

[Octopus]

Hi

Been wiring in a Jacuzzi at a customers.

Wired it to a DP Fused connector unit (to isolate), then to switch junction box.
Switch wire goes to a single pole on/off switch outside the bathroom
The Switched live from Junction box goes to Jacuzzi.

I tested it ALL OK. IR test was +299. RCD Fine. Continuity all fine.

After the tests I still had my Megger attached to the Jacuzzi L + N on Voltage scale.
I noticed that the Megger was reading 180V even though the switch outside the bathroom was OFF.

So I checked FCU, Junction Box, Consumer Unit and switch wiring - Couldn't find anything.

Is this an Inducted 'voltage', that will dissipate?
It does disappear if the FCu is turned off.

Also the Switch cable does run along side 3 other cables and the shower cable too for a short while.
Turning off the shower at the pullswitch didn't make the voltage disappear.

Only things I can think of are -
- Inducted Voltage ?
- Faulty Switch ?
- I've wired the Switch and Jacuzzi the wrong way (Pretty sure I've not, but need to test)

Fast answers appreciated as the customer is already a bit miffed over a couple of other unrelated issues

Hum, so you'll have S/L and P/L in "your" install - are you sure that you have them correctly connected?

 

[stuartcourt]

Whats voltage to earth

 

[Richard Burns]

The line conductor should theoretically be non referenced so any voltage measurement would be suspect. wire an incandescent lamp across line and neutral, see if it glows at all and measure the VD across the lamp, should then be zero. If not then check for wiring faults.

 

[OldTaffy]

All sorted now -Thanks for idea's

FCU was mis-wired, teach me to forget my specs.

So now the 180v has disappeared. All tests ok now

Thanks

 

[Lucien Nunes]

Glad you found it. Would I be right in guessing that the FCU has a neon and the supply and load side of either line or neutral but not both was reversed, so that the neon bridged from supply to load and ended up in series with your MFT? Otherwise presumably you would have discovered during testing that a single-pole switch was in the neutral. Just interested to know...

 

[GLENNSPARK]

Glad you found it. Would I be right in guessing that the FCU has a neon and the supply and load side of either line or neutral but not both was reversed, so that the neon bridged from supply to load and ended up in series with your MFT? Otherwise presumably you would have discovered during testing that a single-pole switch was in the neutral. Just interested to know...

and then there was a deathly silence...

 

[Engineer54]

You might have to wait for another 3 years to hear from him again!! lol!!

 

[GLENNSPARK]

You might have to wait for another 3 years to hear from him again!! lol!!

hmm...
i`l give it.....about 5 weeks....
countdown starts monday morning...