How do you select an earth leakage setting?

Answer 1

on smaller stuff its usually 10ma since that is not usually fatal

default for most gfci

on larger stuff if its not connected with RMC even if you pull a ground wire be very careful

pre made cable BX (MC now) comes in large sizes ive used 2/0

the ground is #6 if there isn't a driven ground on the machine the fault could be carried in the little helix of galvanized wrapped around the cable.

now gee ill just put on an ohmmeter and make sure it wont get red hot

remember the word helix. the dc resistance doesnt change no matter what shape the wire is.

so use an LCR bridge not an ohmmeter

a caution sometimes these use 1000hz as a default

sealtite liqitite greenfeild all have this quirk

some have copper with the galvanize steel but the only thing that changes the inductance is the # of turns (well diameter too)

tray cable does not it seems to be always braided but im not positive

some hi voltage cable has the drain wires in a helix and the runs are usually longer .. on the plus side most bigger stuff has any parameter you could name settable in the breaker.

I did once learn the hard way that the suction hose on a 3" water pump is made with the same helix so it wont be pumped flat

takes about 3 amps at 277V

vom says 12 ohms perhaps its stainless wire

pumps merrily away and the hose steams a bit

perhaps the hose is a better ground than the plate at the bottom of the wood pole

plant has 480 277Y pole looked like one leg grounded delta

takes a bit of thought