Journey Blowing fuses

Just the two of us

New Member
Mar 19, 2023
27
18
3
Umina Beach, NSW
Have recently successfully installed a 3watt GK601 12V Gas Alarm (www.caravanrvcamping.com.au/12v-gas-detector-wall-mounted) tapping power from the bedside lights. (Accept this is not ideal as its powered through a lighting fuse), After installation I realised the alarm does not have a on/off switch and wanted the facility to turn it off when not running gas and have also read where the alarm has sounded when igniting the stove or fridge.

So, in the first case I purchased a simple 20A on/off toggle switch from Jaycar, and installed it on the positive.

Switched the power back on with the toggle switch ON, and it worked perfectly. So far so good.

Flicked the switch to OFF and the 10A fuse blew (dead fuse #1).

Replaced the fuse, and this time set toggle to OFF and after a few minutes switched to ON and the fuse blew (dead fuse #2).

Considering that the toggle switch may be faulty I changed the Jaycar toggle switch for a more robust 12V/100A Isolating Disconnector Cut Off Switch. Acknowledge that these are purposed for battery isolation but thought it could easily handle a simple gas alarm. So, I repeated the earlier tests.

Set the Disconnector Cut Off Switch to ON and turned the power back on and the gas alarm worked perfectly, that is until I changed the Disconnector Cut Off Switch to OFF and another fuse blew (dead fuse #3).

Clearly not learning from my mistakes I tried starting with the Disconnector Cut Off Switch in OFF position and after a few minutes switched to ON. Another fuse blew (dead fuse #4).

My afternoon involved a quick trip to Repco to buy new fuses!

Clearly, I am doing something wrong here. Any insight and guidance would be appreciated.
 

Drover

Well-Known Member
Nov 7, 2013
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I have the exact same unit and really see no need for a ON/OFF switch, that relies on one remembering to get down and turn the alarm ON each time you turn on the gas bottle, it draws bugga all power, I think mine rates in my power audit as 0.25 amp and that should not be a concern .......

Check the polarity of the light circuit, they often not conform to standard procedures, the sensor should not blow any fuses as it would run on a 3 amp fuse happily, sounds like polarity is wrong... don't assume the lead at the switch is from a power source they can be ground.. as I found once after banging a few fuses out, the light was on the battery side of the switch...

Mine is located in a cupboard below the stove and where the gas cocks are for stove and fridge, if stove leaks the gas will go to bottom of cupboard or taps leak, that will set it off, have never had it go off when firing up stove, they live at floor level, it is hard wired into the circuit which provides 12v to my fridge...

If the alarm goes off when starting stove or fridge then that means it working as its supposed to and your stove or fridge isn't....

I would check the wiring as it sounds like you have crossed the wires, check the polarity of your van wires, they are rarely Red and Black with lighting often having one wire with a stripe................

My Carbon Monoxide (CO) Alarm is mounted near the roof and like my Smoke Alarm are active all the time, whether the heater or toaster are operating............
 
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Just the two of us

New Member
Mar 19, 2023
27
18
3
Umina Beach, NSW
Checked and verified the polarity is ok (in fact went OCD and checked the polarity on just about everything). So, while the cut-off has been removed to avoid blowing any more fuses, still have this nagging concern that there is something fundamentally wrong that will become a problem at the worst possible time and place.
 

Drover

Well-Known Member
Nov 7, 2013
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QLD
If still suss about it just fit a fuse inline on pos and neg only need no more than 5a ................... check the continuity of the switch you were using, its the only thing I can think of even though I can't see why unless the switch grounds somehow........ the unit should be on all the time anyway and fitted correctly...
 

Just the two of us

New Member
Mar 19, 2023
27
18
3
Umina Beach, NSW
Thanks Drover for your continued interest. Even thought have set aside the switch idea, it makes me nervous that there is something askew. Once last check with the trusty multimeter and, if I draw a blank, then will get an auto electrician to have a look. Better safe than sorry! If/when the mystery is unraveled will update this post. In the meantime if you (or anyone else) has an apiffany then post away.
 

Drover

Well-Known Member
Nov 7, 2013
12,733
19,467
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QLD
The simply way to check is to use another switch, even an old light switch would do the job, to me it points to the switch otherwise the fuse would blow soon as you hook up the unit........... I wouldn't throw money at a sparky for such a job he will do the same with his meter take a bit longer and charge you........ Really shouldn't have a switch on the sensor anyway, the gas appliance doesn't need to be operating for a leak to happen...
You have it on a light circuit so the fuses fitted are there to protect the wiring so will blow well before a meltdown should happen and with these sensors they just stop working as they are very low power draw..... If it was faulty the fuse would go with or without a switch, my money is on the switch... Its not a double switch with neg and pos connectors ???