Latest Discussions : Electrical & Lighting


03:52PM | 09/28/07
Member Since: 02/17/07
7 lifetime posts
I forgot to turn off the circuit breaker to my air compressor last night. Well, during the night it turned on, and at some point both connecting rods broke. Since it couldn't build pressure, it ran for who knows how long until I heard it running this morning.

Is there a method or system available to prevent an air compressor running uncontrolled for long periods? I thought of using a timer that could be set to run for, say, 30 minutes every time the compressor starts and resets when the compressor turns off. I think that would be long enough since I don't believe I would ever need to operate the compressor any longer, but if it were unattended, short enough to prevent an uncontrolled run time.

I've searched online, but haven't found anything that has a delay longer than 17 minutes.

Any thoughts?




07:37PM | 09/28/07
Member Since: 01/09/07
199 lifetime posts
You mention turning off the circuit breakers at night -- circuit breakers aren't designed to be used as on-off switches, and such use will lead to premature failure of the breaker. If you want to turn the compressor on and off, install a switch.

If you are worried about this happening at night when you're not there, you might look into a clock-type switch, which you can set to turn off the power from, say, 10pm until 7am. Such devices are readily available, and might solve your problem. (Make sure you get one large enough to handle the compressor load -- most of the common ones are for a pretty small load.)


05:37AM | 10/28/07
Member Since: 08/27/07
23 lifetime posts
switch rated breakers can be used as switches, most modern breakers are switch rated now and are marked with a SW or SWR on them identifying them as so. An intermatic 24 hour mechanical timer would suit your purpose you can pick them up at an electrical supply house or even most big box lumber yards have them in the electrical dept.


05:42AM | 10/28/07
Member Since: 08/27/07
23 lifetime posts
the marking on the switch rated breaker is SWD i believe it stands for Switchable Duty....


05:55AM | 10/28/07
Member Since: 02/17/07
7 lifetime posts
Thanks for your responses guys.

The only problem I see with using a typical timer is that no matter what time period I set it to operate, if I'm not there at the shop, such as when I'm at work, I'll be in the same situation.

I think a timer that will only allow the compressor to run a maximum of about 30 minutes would do the trick. That should work since the compressor probably would never run any longer during normal operation, but if it were unattended, it's a short enough time period to prevent it from damage from an extended run time.



06:58AM | 10/28/07
Member Since: 04/25/05
1915 lifetime posts
You can get spring wound timers that range from 15 minutes to 12 hours.

Intermatic is a common brand. But I don't know if any of them are rated to directly control the compressor or if you would need a secondard relay.

Also there are any number of time delay relays that would do that.

Again I don't know if any are rated to switch that kind of load.

Google on that.


01:42PM | 03/07/14
I think this electronic timer should do the trick. It looks as though you just have to run a few wires, create a timing schedule on a device, and it is ready to go! Price point, not bad, especially for the technology used. You can also access your compressor at any time as it allows remote access from your phone. Compared to other digital timers, like Intermatic and Tork, this seems like it would be the best fit.

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