Top Document: Electrical Wiring FAQ (Part 2 of 2) Previous Document: Copper wire characteristics table Next Document: Other links http://www.epanorama.net/wire_mains.html See reader questions & answers on this topic! - Help others by sharing your knowledge Many (most?) building codes now require the installation of smoke detectors in homes. In fact, this has been made retroactive in many municipalities. There are many different types of smoke detectors. Ionization, photo-cell, battery-powered, AC-powered etc. The only thing we're concerned with here, is AC versus battery powered, other than to comment that most building codes are based around ionization detectors, photocell units being usually for somewhat more specialized purposes. All things being equal, in a residential setting with the "ordinary fire", an ionization detector will detect smoke before a photo-cell will - indeed, in some fires, the smoke is almost invisible, and less likely to trip a photo-cell. There is another type of fire detectors - "heat detectors". These work usually by a small piece of special metal melting at 110F or so. These are much better at avoiding false trips. But they usually take much longer to trip than a smoke detector, and should usually only be considered for triggering sprinkler devices (where the consequences of a false trip are quite severe). Heat detectors should not be used as primary fire detection. Most building codes that mandate detectors mandated AC-powered ones for new construction. This is because the statistics show that, in houses equipped with smoke detectors, a lot more people were getting killed in houses with battery-only detectors that had dead batteries than were getting killed in houses where the breakers tripped and killed an AC-only detector. It's also worth noting that some battery detectors are quite sensitive about battery condition. Some even refuse to work if the battery is zinc-carbon (standard cheap battery) instead of alkaline (more expensive). Our building code discourages the installation of smoke detectors on circuits used for other purposes. This means that only a main-panel breaker trip can kill the detectors. A main-panel trip is unlikely even in a fire started by an electrical fault until well after the fire has really engulfed the home. These codes also usually require that the AC detectors be interconnected so that if one triggers, they all sound the alarm. This is usually done by an additional wire between the units. The above suggests that the best way of doing things is to have one circuit dedicated for smoke detectors, and you run 14-3 between each of the detectors - the red wire being the "gang trip" control. If you're still concerned about losing power and thereby losing your detectors, we suggest either the use of detectors that run off AC power with battery backup, OR, adding battery detectors into a system that's already adequately covered with AC detectors. Battery-only detectors should only be considered a stopgap measure in putting detectors into a house that doesn't have any detectors at all, or adding redundancy into a system that already has AC detectors. We also suggest that, if you have battery detectors, you make changing the battery a yearly (or semi-yearly) scheduled event. Some people change the batteries on their birthdays. Others change the batteries during a "daylight/standard time change" maintenance pass. In Canada, the day before the standard/daylight time change (a Saturday) now seems to be officially called "smoke detector battery day" ;-) We don't recommend waiting for the detector to tell you that the battery is dead, unless you manually test the detector monthly. User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: Electrical Wiring FAQ (Part 2 of 2) Previous Document: Copper wire characteristics table Next Document: Other links http://www.epanorama.net/wire_mains.html Part1 - Part2 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: clewis@ferret.ocunix.on.ca (Chris Lewis)
Last Update March 27 2014 @ 02:11 PM
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I bought a new receptacle and installed the same. I still have no power I suspect there could be a bigger problem,this is aluminum wiring.
I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit.
I have multiple switches to lights. Ran 12/2 and 14/3 into switch box and inspector wrote correction needed.
What should I have done instead?
thank you
dennis
Ex: 15 amp-14awg. 12awg-20amp only rule for thumb other factors such as continuous load,heating and others if you do not know the safe NEC rules then please call a qualified journeyman Electrician better be safe