Voltage on ungrounded drain

[Stan Stephan]

Cable was 600 V rated UL type TC, single pair with drain wire and aluminum mylar shield. Circuit 120 Vac to operate solenoid. Drain was floating not grounded (installation error). Plant personnel noticed some voltage tickle on a metal junction box. As experiment, plant personnel took 50 ft of same cable and hooked one insulated conductor to hot side of 120 V office outlet. Everything else floating. Electrician used VOM and measured 120 V on drain to outlet ground. Cable had been meggered and had good insulation resistance between insulated conductors and conductors to shield/drain. Can anyone tell me cause of voltage measured on drain to ground? In correct installation with drain wire grounded circuit functions properly.

 

[gar]

10104-2341 EST

Capacitance coupling from hot wire to shield and drain wire.

.

 

[LEO2854]

Cable was 600 V rated UL type TC, single pair with drain wire and aluminum mylar shield. Circuit 120 Vac to operate solenoid. Drain was floating not grounded (installation error). Plant personnel noticed some voltage tickle on a metal junction box. As experiment, plant personnel took 50 ft of same cable and hooked one insulated conductor to hot side of 120 V office outlet. Everything else floating. Electrician used VOM and measured 120 V on drain to outlet ground. Cable had been meggered and had good insulation resistance between insulated conductors and conductors to shield/drain. Can anyone tell me cause of voltage measured on drain to ground? In correct installation with drain wire grounded circuit functions properly.

something is not grounded properly:-?

 

[Smart $]

10104-2341 EST

Capacitance coupling from hot wire to shield and drain wire.

.

That and high impedance across the measuring instrument.

 

[hurk27]

something is not grounded properly:-?

yea the drain wire:roll:

 

[LEO2854]

yea the drain wire:roll:

thanks hurk the first post is confusing maybe it is plain as day:-?

 

[SG-1]

Here is a NEMA Publication on the subject.

 

[Cow]

yea the drain wire:roll:

Your smart aleck responses crack me up Hurk....:grin: