LED Pilot lamp

This might be symptomatic of high input impedance presented by these devices, and the thing picking up some energising current by stray capacitance.

Try lobbing a suitably-rated resistor across its input terminals for starters, perhaps?

better post a schematic, the problem will be easier to define that way.

Attached is a part of control wiring diagram. Control wirings are enclosed in a wire duct inside a metal enclosure. Wiring for PB's & PL's are binded by a plastic spiral wrap and on wire ducts at the back of panel door

The wire between the LED and the limit switch could be capacitively coupling to the metal duct for a ground ( see PWSlack - above). Or, it could be inductively coupling to another wire for L1. The resistor that PW suggests could bleed off that coupled current. You may find it desireable to place a relay coil in place of the LED, then run the LED from the relay contact.

In the contactor 13/14 auxilliary(NO) contact,power yr LED from 14 (output) and then the second leg to neutral.Use a much smaller wire size for the LED.When yr contactor is energised,it should glow and when de-energised it should go off.

If the problem persist,pick a second 13/14 auxilliary(NO) contact of same contactor and supply neutral to the second leg of the LED thru this contact.In this way both life and neutral(220V) is disconnected from the LED when the contactor is de-energised and your LED will surely go off.Both contacts will open at same time.

If u dont have extra free NO contact,attach seperate auxilliary contacts to the contactor on top or by the side,depends on which make of contactor u use (Telemecanique,siemens,ABB etc).Auxilliary contacts are less expensive.

Patrick Whowha