AC voltage leaking across breakers

[Windwalker44]

Hi, I’m hauled out in Florida preparing my boat for a launch the first of the year. I’m installing a new battery charger because the prior one got fried from a lightning strike in the spring.
The leads to the charger before making any connection are reading 120 volts from shore power with the beaker closed. When I open the breaker I’m still getting a tester reading of 70 volts.
I tested all the AC breakers by taking a reading from the posts and all read 120 volts closed and all read various voltages from 30-70 when the circuit was open and it should have read zero. I can’t figure out what is causing a leakage at various values but consent variousness.
Thank for your help

[pcmm]

When you replaced the charger due to a lightening strike, did you also replace any other hardware in the electrical system? Sounds like your breaker panel is also affected

[wholybee]

A floating neutral can cause that. The actual problem could be anywhere from the pedestal on the dock to the breaker panel itself. Measure between neutral in one place, and neutral in another place. Not the hot side anywhere, stay on the neutral side. It should always be close to 0 volts. If not, there is a problem between the 2 places.

To help you understand what is going on. Imagine the neutral instead of being 0V, it is floating at around 70V. With the breakers off, you measure between the load side of the breaker, and neutral. You have 70V going backwards through whatever device is on the breaker from neutral to where you are measuring. Different devices will have different impedances to this reverse voltage, so the voltage you measure will be different on each breaker.

It might require an electrician to find. Be very careful, as a floating ground is a very lethal problem. You also might find you need to replace more than just the charger that was damaged by the lighting strike.

It might be something else entirely, but that is my first guess, and I have encountered it before.