I almost killed myself. What an idiot

[mcanderson]

So my aircon was making strange sounds which I traced to the pump which drains the condensation water away. Simple short term fix was to disconnect it and allow condensation water to drain to the bilge.

However, I didn’t disconnect the ac power and so when I touched the live wire connection it was strangely live. A nice bang, and luckily the shore power rcd kicked in. One shaken boat owner!

 

[Bouba]

That would have put a dampener on the raft up:nonchalance:

 

[Portofino]

There should be a boat RCD too , the thing that trips occasionally if you have too much AC load on simultaneously.
Anyhow yup the Aircon is AC and normally there’s drip trays under the units or air handlers.

So water very close to AC potentially dangerous, compounded by relative inaccessibility of the units under furniture etc .

Every now and agian I check and clean the air IN filters ( get dusty and decrease performance) and the drains to make sure the water can get out properly.

Normally the system is off at the breaker panal .
How ever with any AC ( the 220 v current ) work I don,t trust the main breakers so allways unplug the shore power as well .

Eg I replaced the geny bat charger / conditioner - even though it was supposed to switched off at the panal I unplugged the boat - just in case .
Replaced a 220 V socket - again even though the AC 220 V socket breaker was off and stuff plugged in not working I still pulled the shore power plug out —-
You just don,t know if a fault is lurking about making the bit you are fiddling about with live ,or it’s not your “ lucky day “ and the RCD ,s don,t work ?

 

[simonfraser]

glad you are still upright.
insulated thin nosed pliers, short the connectors you are about to touch, preferably b4 you think you have disconnected to power. works every time without killing yourself.

 

[JerryC]

glad you are still upright.
insulated thin nosed pliers, short the connectors you are about to touch, preferably b4 you think you have disconnected to power. works every time without killing yourself.

So the OP has admitted he got a belt through a moment of thoughtlessness and you're inviting him to be deliberately reckless? Sheeesh. Once you've seen a pair of needle nose pliers accidentally spot welded to mains terminals you might like to refrain from offering this advice. Do things properly, turn the 240v off and pull the plug for good measure. Tell your crew not to reconnectit. If you wanna double check connections are not live, use a multimeter with proper insulated probes or non contact mains voltage detector.

 

[Deleted User YDKXO]

However, I didn’t disconnect the ac power and so when I touched the live wire connection it was strangely live. A nice bang, and luckily the shore power rcd kicked in. One shaken boat owner!

I always think with electric shocks, what doesnt kill you makes you stronger

 

[mcanderson]

Thanks Mike. Makes me feel much better.

 

[simonfraser]

So the OP has admitted he got a belt through a moment of thoughtlessness and you're inviting him to be deliberately reckless? Sheeesh. Once you've seen a pair of needle nose pliers accidentally spot welded to mains terminals you might like to refrain from offering this advice. Do things properly, turn the 240v off and pull the plug for good measure. Tell your crew not to reconnectit. If you wanna double check connections are not live, use a multimeter with proper insulated probes or non contact mains voltage detector.

haha, noooooo the idea is to isolate it FIRST
then double check with the pliars rather than your fingas !!

 

[JerryC]

haha, noooooo the idea is to isolate it FIRST
then double check with the pliars rather than your fingas !!

Simon, you've been told by two separate people now why that isn't a good idea. No qualified sparky would ever endorse such a caveman approach to mains electrics, least of all on a boat! If you can't see the faulty logic in your suggestion then one day you're going to end up killing yourself or worse still, killing someone else.

 

[simonfraser]

i don't claim to be an electrician or be better than one.
just pointing out that the initial poster nearly killed himself with a mistake.
we all make mistakes, well most of us.
yes you can and should use a meter, switches etc etc, however they can all fail.
the faulty logic is not using a fail proof way to triple check the supply has really been disconnected, might save your life one day.

 

[penberth3]

i don't claim to be an electrician or be better than one.
just pointing out that the initial poster nearly killed himself with a mistake.
we all make mistakes, well most of us.
yes you can and should use a meter, switches etc etc, however they can all fail.
the faulty logic is not using a fail proof way to triple check the supply has really been disconnected, might save your life one day.

Competent people know how to do this with meters or test lamps, without causing any damage to tools or the installation.

 

[markc]

I posted a very similar thread a few months ago, I got a nasty poke and the RCD didn't trip, and I had (obviously badly) checked with a multimeter. I should have just pulled out the shore power lead... we live (just about) and learn!

 

[superheat6k]

Simon, you've been told by two separate people now why that isn't a good idea. No qualified sparky would ever endorse such a caveman approach to mains electrics, least of all on a boat! If you can't see the faulty logic in your suggestion then one day you're going to end up killing yourself or worse still, killing someone else.

Thing is, at some point after properly creating and then properly checking for isolations with a meter, which should itself be checked immediately before the actual test for supply isolation, on a separate supply source, and again directly afterwards, however for a boat ideally with the shore power lead un plugged, at some point a first touch of the live conductors might be necessary, i.e. when undoing bolted connections on heavy cables.

I do a flying finger test - with my hand in motion I let one finger brush past the terminal. The motion means I cannot make a lock on contact should it be live or have some form of capacitance still attached, e.g an inverter, or sometimes a single phase motor. Better this than going onto the terminal with both hands gripping onto a steel ratchet only to then find 'an issue' with the isolation.

I work on 400VAC 3 phase systems, and they do not take prisoners. I take electrical isolations very very seriously.

 

[JerryC]

Superheat6k, I also take high voltage isolation extremely seriously, that's why I'm still alive, lol. Re your paragraph 2 ... please enlighten us - why do you use a finger flyby rather than a meter? Regards 240v ac on boats, in my experience, once you've switched EVERYTHING off, pulled ALL the plugs out and informed your crew not to reconnect, the only danger I can see is from capacitors storing high voltage DC. That will only be inside things like battery chargers but not for very long.

Edit: and maybe inverters too, but I don't have one so I wouldn't know, but don't they have an isolating breaker too?

 

[superheat6k]

Superheat6k, I also take high voltage isolation extremely seriously, that's why I'm still alive, lol. Re your paragraph 2 ... please enlighten us - why do you use a finger flyby rather than a meter? Regards 240v ac on boats, in my experience, once you've switched EVERYTHING off, pulled ALL the plugs out and informed your crew not to reconnect, the only danger I can see is from capacitors storing high voltage DC. That will only be inside things like battery chargers but not for very long.

Edit: and maybe inverters too, but I don't have one so I wouldn't know, but don't they have an isolating breaker too?

Please re-read my post - paragraph one clearly states it is vital to properly check for no power, and having disconnected the mains, WITH A METER that itself should be tested on a separate source both before and after the test on the conductors being checked.

 

[JerryC]

Yeah yeah, I thought I'd said all that about very thorough checking of isolation and checking with meters back in post #5, maybe you missed it? This is the 21st century, there are proper tools for checking for isolation and they are cheap enough, so I still don't get this shorting out with with pliers or 'nearly' touching with a flyby finger approach. We can agree on thing though, 240 volts is fatal in the wrong hands, especially when there is water in close proximity.

 

[MrB]

Yeah yeah, I thought I'd said all that about very thorough checking of isolation and checking with meters back in post #5, maybe you missed it? This is the 21st century, there are proper tools for checking for isolation and they are cheap enough, so I still don't get this shorting out with with pliers or 'nearly' touching with a flyby finger approach. We can agree on thing though, 240 volts is fatal in the wrong hands, especially when there is water in close proximity.

I fully agree with JerryC so I also must be a troll .

 

[Assassin]

You can switch everything off and if someone had bodged something or bypassed something previously, which you are unaware of then you can still be electrocuted.

Simple solution is called a DLI or dead line indicator, available for around £5 upwards they are a godsend, some are battery powered while others are rechargeable, simply place the appropriate end next to the cable or item you are testing and it lights up if it is live, no touching necessary, no contact with a meter which is not infallible as a bad contact will result in no reading, and you know you will not electrocute yourself, should be standard equipment in the toolbox.

I have an all singing and dancing one given to me by one of our suppliers ( I love free) and it detects AC and DC, allegedly from 12 volts upwards, but in reality it detects the 5V if the end is in close proximity to a wire or cable, it is totally sealed and approved for use in hazardous environments such as open fuel tanks and even has a British Coal approval for use in mines.

Every electrician I know have a few in their kit and while you can spend as little as £5 on one, you can spend considerably more if you require an all singing and dancing item.

 

[sorabain]

You can switch everything off and if someone had bodged something or bypassed something previously, which you are unaware of then you can still be electrocuted.

Simple solution is called a DLI or dead line indicator, available for around £5 upwards they are a godsend, some are battery powered while others are rechargeable, simply place the appropriate end next to the cable or item you are testing and it lights up if it is live, no touching necessary, no contact with a meter which is not infallible as a bad contact will result in no reading, and you know you will not electrocute yourself, should be standard equipment in the toolbox.

I have an all singing and dancing one given to me by one of our suppliers ( I love free) and it detects AC and DC, allegedly from 12 volts upwards, but in reality it detects the 5V if the end is in close proximity to a wire or cable, it is totally sealed and approved for use in hazardous environments such as open fuel tanks and even has a British Coal approval for use in mines.

Every electrician I know have a few in their kit and while you can spend as little as £5 on one, you can spend considerably more if you require an all singing and dancing item.

Out of interest, is the general procedure to first check that your "live line detector" still works by testing it when the line is expected to still be live, then isolate and try again? Just wondering how you tell the difference between "not live" and "handheld broken". I had some excitement in the past from someone bodging and bypassing mains in my house :|

 

[penberth3]

Out of interest, is the general procedure to first check that your "live line detector" still works by testing it when the line is expected to still be live, then isolate and try again? Just wondering how you tell the difference between "not live" and "handheld broken". I had some excitement in the past from someone bodging and bypassing mains in my house :|

First check your tester on something you know is live, then check the circuit you're working on, then check the tester again on a known live.

Edit: Superheat says the same thing above.