Did a search but could not find much discussions on the captioned; which I think is very important considering the huge capacity of water we're handling and especially when electrical items are submerged (eg. pumps, wavemakers, heaters etc) and also falling of lighting fixtures and so on.
Here's my compilation:
1. Number ONE "Must Have - ELCB Plug/Adaptor
If a submerged electrical item has a earth leakage, your fishes may swim normally but you WILL receive electrical shocks (minor) or electrocution (worse) the moment you put your hands in the water. (The hand serves as a electrical return through your body to the ground)
The ELCB Plug/Adaptor, having a typical tripping current of 10mA or 30mA (get the 10mA ones), will save your life by tripping the circuit the moment a live or earth fault is detected including water splashes on any electrical sockets:
DO NOT depend solely on the Master Circuit Breaker (MCB) which was mandated in every households. It will trip almost instananeously if there's a earth/current leakage BUT may NOT be FAST ENOUGH to stop the current from killing you (main "culprit" - Excessive Cable Length).
The ELCB Plug/Adaptor will trip within a heartbeat fast enough (forgotton the specs - in terms of nanoseconds) to stop the current (including the weaker harmless ones) from reaching you.
(1) The ELCB Plug/Adaptor must be attached to the wall socket (not extension sockets)
(2) If you use an extension cable, make sure the total cable length is NOT >15m. Anything longer WILL NOT WORK. (Simple electrical law: Voltage = Current x Resistance.... where Voltage & Current (tripping current) are constant and Resistance the only variable and is affected by the cable diameter, resistivity and most importantly... length
*Disclaimer: I'm only familiar with the 2 brands depicted in the above pictures. If you do purchase other brands; pls read manufacturer's instruction very carefully especially on the rated tripping current and recommended max cable length.
* ELCB = Earth Leakage Circuit Breaker (some countries called it RCCB, Residual Current Circuit Breaker or GFCI, Ground Fault Circuit Interruptor in the USA)
2. Number ONE "Must Know"
When electrocuted, why some people died and some only received electrical burns? (same current rating in both scenarios)
The answer lies in the "path the current travalled". In short... if a current travel pass your heart
, you can kiss the world goodbye....
Now all of us know that current travels "everywhere" and fastest by the shortest path especially mediums with the least resistance...
If you put only 1 hand, say your right hand, into the tank (with electrical leakage), the shortest path for the current to travel is:
Right hand -> torso (right flank) -> right leg -> ground
The current did not travel pass your heart, you'll get electrical burn and won't get electrocuted (in most situations except extreme cases...).
If you put both hands into the tank, the shortest/possible paths for the current are:
1 hand -> heart -> the other hand -> tank water or/and
Right hand -> heart -> left leg -> ground or/and
Left hand -> heart -> right leg -> ground.
The current crosses the heart in all the above paths and fatality is almost guaranteed.
1) Install the ELCB Plug/adaptor (strongly recommended to every aquarium/pond owners)
2) Cultivate the habit of putting only 1-hand into the tank (if need to) and the other hand into your pocket (or elsewhere)
as much as possible.
3) Keep the floor dry whenever practicable.
4) Forgotton the most important 1.... Swtich off your mains when performing tank maintenance or when you need to put hands in it.
5) There's also this rubber gloves that can cover the entire length of your arm