Smoke Detector with relay to switch off external device

[asteven221]

Does anyone know of such a device?

I would like to be able to cut mains power to the boat if the smoke detector triggers. That seems to be a simple enough thing to do however I can't find anything via Google that looks ideal.

 

[asteven221]

Just stumbled on this on Amazon.

Kidde SM120X Interconnect Accessories Smoke Relay Module​

Looks like to the sort of thing I am after!

 

[Refueler]

I used to modify Smore Detectors and give them to people as bilge alarms ...

Inside the detector is a small relay - that the TEST button triggers ... that relay can be used to sort so many things - such as your idea.

Basically I would be using the detectors relay to trigger a high power relay that then cuts off the mains power to boat.

But of course if the Kidde does the job ... then thats the answer.

 

[PaulRainbow]

Just stumbled on this on Amazon.

Kidde SM120X Interconnect Accessories Smoke Relay Module​

Looks like to the sort of thing I am after!

That's not rated for your shore power, you would need to use it to trigger a heavier duty relay, such as a Finder 22 series.

This would do the job, fitted immediately after your RCD. Choose an appropriate coil voltage to go with the Kidde relay.

 

[wonkywinch]

I would be concerned that once a fire had started that removing a possible source of ignition (electrics) would be too late as the triangle would self sustain.

 

[ylop]

I would be concerned that once a fire had started that removing a possible source of ignition (electrics) would be too late as the triangle would self sustain.

If you've got the actual flames stage then your are probably right - although it may burn itself out if you are really lucky. I guess the OP is hoping that the smoke detector is triggered when the wiring or component gets too hot and starts to melt etc - which depending on where the component is and where the smoke detector is, is not entirely impossible but it perhaps isn't that likely unless you've specifically got a particular bit of equipment in mind and so placed the smoke detector ideally for it. In that case it doesn't seem like the best risk mitigation...

 

[rogerthebodger]

If you've got the actual flames stage then your are probably right - although it may burn itself out if you are really lucky. I guess the OP is hoping that the smoke detector is triggered when the wiring or component gets too hot and starts to melt etc - which depending on where the component is and where the smoke detector is, is not entirely impossible but it perhaps isn't that likely unless you've specifically got a particular bit of equipment in mind and so placed the smoke detector ideally for it. In that case it doesn't seem like the best risk mitigation...

That's the function of the fuse, circuit breaker or RCD so I doubt a smoke power shut off as said would be too late

IMHO the power from the DC supply would be more likely to cause a fire than mains so a relay in the DC supply driven by a smoke detector would be better

 

[PaulRainbow]

That's the function of the fuse, circuit breaker or RCD so I doubt a smoke power shut off as said would be too late

IMHO the power from the DC supply would be more likely to cause a fire than mains so a relay in the DC supply driven by a smoke detector would be better

The DC supply should also have circuit protection.

 

[rogerthebodger]

The DC supply should also have circuit protection.

Yes but will be at a much greater current rating than the 24o Vac inlet it also will not have an RCD

On my boat my main domestic fuse is 600 amps to accommodate my bow thruster then several CB of a rating to protect the individual smaller cables depending on the current for the various kit

My main supply cable from my batteries are 38mm x 20 mm busbars to my bow thruster / windlass with a lower CB in the feed to the windlass as the cable is smaller than the 600 amps main supply

 

[PaulRainbow]

Yes but will be at a much greater current rating than the 24o Vac inlet it also will not have an RCD

Higher current = higher rated circuit breakers or fuses. The RCD is irrelevant, it's not strictly speaking a over current protection device.,

On my boat my main domestic fuse is 600 amps to accommodate my bow thruster then several CB of a rating to protect the individual smaller cables depending on the current for the various kit

My main supply cable from my batteries are 38mm x 20 mm busbars to my bow thruster / windlass with a lower CB in the feed to the windlass as the cable is smaller than the 600 amps main supply

All circuits should be adequately protected against over current. If you have any cables that can produce smoke, there is something wrong with your systems.

 

[ylop]

Yes but will be at a much greater current rating than the 24o Vac inlet it also will not have an RCD

On my boat my main domestic fuse is 600 amps to accommodate my bow thruster then several CB of a rating to protect the individual smaller cables depending on the current for the various kit

My main supply cable from my batteries are 38mm x 20 mm busbars to my bow thruster / windlass with a lower CB in the feed to the windlass as the cable is smaller than the 600 amps main supply

But those cables etc presumably aren’t sitting out in the middle of the saloon. Typically the batteries are tucked away somewhere and the cables run behind settees/cabinets/headlining etc to get to where it’s needed. If those cables get hot enough to smoke it will take quite some time before that smoke finds its way out of the void spaces into the cabin and triggers a smoke detector. By that point has the wiring or things it is in contact with for hot enough to sustain combustion even after the power is isolated?

 

[rogerthebodger]

By that point has the wiring or things it is in contact with for hot enough to sustain combustion even after the power is isolated?

That is the first point of my post #7

The point about time for smoke to perminate is valid but if the boat is unoccupied there is time but still too late