Chocolate fireguard
Active member
There is an active topic in the Peak District section where the subject of running an electrical supply to a distant underground pump is briefly discussed.
I think similar things have been done by some in the caving community in the past on an ad hoc basis but I have never seen anything you could call a technical discussion on the subject, by which I mean an attempt to answer some (fairly obvious?) questions such as:
What voltage is considered safe in a caving environment (and with reasons)?
Does the supply need to be earthed?
If so, and you are using a portable generator out in the sticks, how do you go about doing that?
Is an RCD needed as well as the fuse/mcb?
Is putting up with cable resistance dropping the voltage, then using a transformer at the end to raise it again, acceptable - bearing in mind that if the pump/whatever is not running the full voltage appears in the cave?
Is it advisable to use one of the modern systems that provide a supply isolated from earth but disconnect when a break in each conductor is detected?
I am not looking for a discussion on voltage drop/cable size.
If I was in a low wet cave passage alongside a cable carrying a 230V supply, let alone sharing the Mucky Ducks or the Wet Wallows with a 2kV supply, I would want to know that the people who had installed it had given a bit of thought to the above questions.
I think similar things have been done by some in the caving community in the past on an ad hoc basis but I have never seen anything you could call a technical discussion on the subject, by which I mean an attempt to answer some (fairly obvious?) questions such as:
What voltage is considered safe in a caving environment (and with reasons)?
Does the supply need to be earthed?
If so, and you are using a portable generator out in the sticks, how do you go about doing that?
Is an RCD needed as well as the fuse/mcb?
Is putting up with cable resistance dropping the voltage, then using a transformer at the end to raise it again, acceptable - bearing in mind that if the pump/whatever is not running the full voltage appears in the cave?
Is it advisable to use one of the modern systems that provide a supply isolated from earth but disconnect when a break in each conductor is detected?
I am not looking for a discussion on voltage drop/cable size.
If I was in a low wet cave passage alongside a cable carrying a 230V supply, let alone sharing the Mucky Ducks or the Wet Wallows with a 2kV supply, I would want to know that the people who had installed it had given a bit of thought to the above questions.