Surprised by current across neutral

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Hi all, I removed a heater circuit timer after turning off the 30a circuit breaker that protects it. With the breaker turned off and the timer removed, I was surprised to see that there was current across the load-side neutral and various other wires: the load-side live, the load-side earth, and the supply-side neutral.

Is that to be expected?

This is a setup from the 1980s. I've used American terminology--apologies for any confusion.
 
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Please describe exactly how you are detecting this current.
 
Do you mean current? Or do you mean voltage?

How much did you measure?
 
Please describe exactly how you are detecting this current.
Sorry, sounds like maybe current was the wrong term--my error. An analog voltage meter showed 200-240 volts across the different connections.

On further investigation, there is another heater circuit that seems to be connected somehow. When I turn off the breaker to this second heater circuit, there's no longer any voltage across any of the wires on the first circuit I mentioned above.
 
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There are at least two probable auses. If you can do it safely, leave the first breaker off, and the second breaker on, connect a substantial load, such as a heater, to the first circuit, and measure the voltage again.
 
There are at least two possible causes. If you can do it safely, leave the first breaker off, and the second breaker on, connect a substantial load, such as a heater, to the first circuit, and measure the voltage again.
I've now removed the timer from the second circuit, so I can't duplicate the original conditions. Having that 2nd timer gone seems to prevent the surprising-to-me readings. There was a neutral connected to the second circuit's timer that I can't visually trace (to provide power to the timer, I assume). Is it possible that that neutral was allowing the readings I was getting?
 
I am suspecting a borrowed neutral, today with RCD protection getting rare, but before the RCD it was easy to make an error, and the neon screwdriver is your friend today we have the clamp on ammeter, but in the past the neon screwdriver has saved me.

But from what you say hard to work out.
 

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