I have three electrical smoke detectors and I'm replacing one. I don't know whether or not they are on a single circuit. The directions say for alarms that are used as a single station (I don't know what that means), do not connect the red wire to anything. When alarms are interconnected, all interconnected units must be powered from a single circuit. All I can tell you is that when I removed my old smoke detector, there was a male plug attached to all three wires. There was a female plug attached to all three house wires. When I tested the electrical current, my voltmeter shot up when I tested the red and black lines and then again when I tested the black and white lines (connecting the red voltmeter wire to the white). It does nothing when I connect red and white (connecting the black voltmeter wire to the white). If I remember correctly, all three smoke detectors do not go off at the same time. For example, when I am cooking, I think I remember that the one near the stove goes off, but not the other two.
you could definetly get a fire cape. you have 3 mill, so spend it maybe on some barrows. either that, or a barrows top, some dragon platelegs, a dragon med or other good helms, a d sq if you finished legends (if not maybe a crystal or just rune, no obby) some d boots, if you have done recipe for disaster, some dragon gloves, or dragon gauntlets from fist of guthix. you should also bring a fremmy, zammy/sara/guthix, or obby cape, a glory ammy or any other that you suit, and fills your inv up halfway with sharks or tuna potatoes (heal 22), and half with prayer and other pots.
You do not want to mix chemicals together. There was a guy at work that was cleaning the walk-in ovens. Wash down the ceiling, walls and floor but not his gloves. Switched to another chemical which reacted with the chemicals on his gloves and created a weak mustard gas. He used his teeth to remove the gloves and his face / mouth / tougue / gums were also badly burned. Some household chemicals used in the bathroom and mixed with bleach can cause a poisonous gas. Knock you unconcious and suffocate.