ELECTRICITY AROUND THE POND
Importance of safety and ponding - One thing not to mess with around your pond or water feature is your safety. Everyone knows electricity and water does not mix. GFI or Ground Fault Interrupters, are a definite must have when it comes to breaking the "JUICE" before electrocution.
A GFI will only trip if there is a function ground circuit connected to the device or pond etc.
Recently there have been what I would regard as a few misleading posts about electrical safety around the pond. Before these I had said I would do an 'experiment' to demonstrate some points, well I finally got off my rear end and did the experiments.
DO NOT ATTEMPT TO RECREATE THE EXPERIMENTS IN THESE PHOTOS UNLESS YOU KNOW WHAT YOU ARE DOING.
It would actually be useful if someone Stateside who DOES KNOW WHAT THEY ARE DOING did recreate them with a US spec GFI, I think your 'lightest' trip is 5mA, whereas ours, as far as I know, is 30mA and the one used in this experiment is a '30mA' trip. I actually checked it a while a go and from memory it trips somewhere around 25mA, which is good.
You should note I am wearing two layers of latex gloves and on my feet all through the experiment wearing rubber wellies.
Photo 1) the apparatus, inspection lamp on, a plastic bucket, to simulate the pond liner, full of pond water, an inspection lamp to show that the power is there, suitable extension cables.
The power comes from the cable with the black socket and the opened plug, the extension that starts with the open plug ends in the white socket and the socket feeds the inspection lamp.
Photo 2) the earth/ground wire in the open sockey has been disconnected.
(Sorry it is blurred I didn't realize the camera had focused on the meter
rather than the plug.) This mean that the inspection lamp is
unearthed/ungrounded.
Photo 3) the white plug and socket in the bucket of pond water with the light still lit, note no RCD/GFI protection at the moment on the inspection lamp
Photo 4) plug and socket in the water, lamp lit and meter showing the
voltage between the water 4 or 5 inches from the live/hot socket and
electrical earth/ground. 121.5V. Note the supply voltage was around 238V
during this experiment.
Photo 5) RCD/GFI added BUT the earth/ground to the lamp is STILL disconnected, the 2nd meter is showing the voltage between the water and the actual wet soil under the bucket 118V, I can't read the other meter, sorry
It doesn't show very well but the lamp is still fully lit, IE, THE RCD/GFI DID NOT TRIP!!!!!!!!!!!!!!!!!!!!!
The above is the situation present with a faulty two wire device with no grounding of the water EVEN IF A GFI IS PRESENT
Photo 6) a clear shot of the voltages between the water and electrical earth/ground and between the water and the soil
As soon as I touched the disconnected earth/ground wire to is pin the RCD/GFI tripped, i.e. the electrical earth/ground from the lamp carried some of the current otherwise destined for the neutral and thereby creating a 25mA+ difference between the current flowing in the live/hot and neutral circuits within the RCD/GFI and tripping the RCD/GFI
Photo 7) Earth/ground again disconnected but the water earthed/grounded through the meter, which is set to measure current, to the soil. The meter set that way is effectively a direct short, the current shown is 16.8mA, the RCD/GFI did not trip.
It would have with a 5mA tripping GFI.
Photo 8) RCD/GFI removed but the earth/ground reconnected, the plug and socket are still in the water and no fuse blew
The eagle eyed may spot that the cable is old, old colour scheme, but it is still good.