Author Topic: On / off switches  (Read 1141 times)

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Offline JalcaTopic starter

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On / off switches
« on: May 19, 2022, 01:03:26 am »
Assuming that appropriate soft starting measures are taken where it's appropriate, is it acceptable / good engineering practice  to not have a device mounted on / off switch and to use the switch on the wall socket to turn power on and off (e.g. in a power supply) instead?

I'm thinking that potential arcing on the wall switch (depending on what is being switched) could still be an issue over time, but I'm not sure of this or whether there are other reasons that may make a device mounted switch necessary / good practice.

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Online themadhippy

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Re: On / off switches
« Reply #1 on: May 19, 2022, 01:12:42 am »
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whether there are other reasons that may make a device mounted switch necessary / good practice.
accessibility,what if the nearest socket is under a desk or behind a cupboard?  and not all sockets are switched  ,example all of my home ents kit is plugged into a block of 8 un switched sockets,if i turned it on/off  from the wall everything would come on.
« Last Edit: May 19, 2022, 01:15:52 am by themadhippy »
 
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Offline JalcaTopic starter

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Re: On / off switches
« Reply #2 on: May 19, 2022, 02:59:07 am »
Sorry, I should have clarified. Assuming that turning on and off from the wall socket is what is wanted. If for example, I were to design and build a PSU, is it good practice / acceptable to not include a device mounted on / off switch and just use the wall socket? Is there an electrical / technical reason why the wall switch should not be routinely used for this purpose?

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Offline bob91343

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Re: On / off switches
« Reply #3 on: May 19, 2022, 04:49:13 am »
I have done that with no problems.
 
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Offline BeBuLamar

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Re: On / off switches
« Reply #4 on: May 19, 2022, 11:06:33 am »
Sorry, I should have clarified. Assuming that turning on and off from the wall socket is what is wanted. If for example, I were to design and build a PSU, is it good practice / acceptable to not include a device mounted on / off switch and just use the wall socket? Is there an electrical / technical reason why the wall switch should not be routinely used for this purpose?

Cheers

Well in my house there is a wall switch for the outlet underneath the kitchen sink for the garbage disposer. It makes sense. Some house with wall switch to turn on/off outlet in the bedrooms. It's OK too. I don't see no harm in most cases but I wouldn't want too many of those switch outlets in my house. Sometimes you are not sure the outlet is on or off because the wall switches are not near the outlets
 
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Offline madires

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Re: On / off switches
« Reply #5 on: May 19, 2022, 11:30:13 am »
Nothing wrong with not having a power switch in a device and powering it via a switchable wall socket. For example, most power bricks come without any power switch.
 
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Offline david77

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Re: On / off switches
« Reply #6 on: May 19, 2022, 11:41:06 am »
If it is something you want to sell in different markets you should keep in mind that most countries do not use switched sockets.
 
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Offline wizard69

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Re: On / off switches
« Reply #7 on: May 19, 2022, 08:16:29 pm »
Sorry, I should have clarified. Assuming that turning on and off from the wall socket is what is wanted. If for example, I were to design and build a PSU, is it good practice / acceptable
To an extent that varies a lot from country to country.  In general and in the case of a PSU; I'd have to say it is universally bad practice.    In the case of the NEC I believe that it might not pass muster depending upon several factors.   One question would be the proximity of the switch.   

My NEC knowledge is rather old and frankly not up to date but in the past you had to have a local switch at the tool that was being used or some sort of overload protection for motor driven devices.   This largely was applied to motor driven stationary tools as a running tool could overload and thus over heat.   A power supply would or could have the same implied risk and devices like welders are required to have a local switch last I knew.

In any event if you forget the rules that apply for your area for a bit, I'd have ot ask why would you do this to yourself?   Having a switch on a power supply would be the first thing I'd allocate panel space for.
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to not include a device mounted on / off switch and just use the wall socket? Is there an electrical / technical reason why the wall switch should not be routinely used for this purpose?

Cheers

I can't think of a technical reason, I mean it could work, would it meet code requirements I don't know.   However if safety and convenience are a factor in your life, a switch makes a lot of sense!
 
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Offline JalcaTopic starter

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Re: On / off switches
« Reply #8 on: May 19, 2022, 11:40:29 pm »
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In any event if you forget the rules that apply for your area for a bit, I'd have ot ask why would you do this to yourself?   Having a switch on a power supply would be the first thing I'd allocate panel space for.

I've seen audio setups where all devices are plugged into one or two appropriately sized power strips that then go to a conveniently placed and appropriately sized switched wall socket(s). All devices had device mounted switches but were left in the 'on' position allowing the whole system to be switched on or off from the wall socket(s). In this scenario it was more convenient to turn on one or two switches than it was to turn on ~6 - 8. It occurred to me that maybe cutting out the middle man (the device mounted switch) could be an option in circumstances like this. But I was unsure if this would be good practice / allowable or not. One argument for doing this that I can think of would be that the mains could go directly to the trx and perhaps reduce the number of failure points within the device where a mains connection could fail and lead to problems.
« Last Edit: May 19, 2022, 11:42:07 pm by Jalca »
 

Online themadhippy

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Re: On / off switches
« Reply #9 on: May 20, 2022, 12:26:37 am »

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I've seen audio setups where all devices are plugged into one or two appropriately sized power strips that then go to a conveniently placed and appropriately sized switched wall socket(s). All devices had device mounted switches but were left in the 'on' position allowing the whole system to be switched on or off from the wall socket(s).
great way to increase the risk of blowing your speakers
 
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Offline JalcaTopic starter

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Re: On / off switches
« Reply #10 on: May 20, 2022, 02:55:54 am »
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great way to increase the risk of blowing your speakers

Okay, how so? Would muting / disconnect circuits not protect the speakers?

 

Offline madires

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Re: On / off switches
« Reply #11 on: May 20, 2022, 08:05:59 am »

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I've seen audio setups where all devices are plugged into one or two appropriately sized power strips that then go to a conveniently placed and appropriately sized switched wall socket(s). All devices had device mounted switches but were left in the 'on' position allowing the whole system to be switched on or off from the wall socket(s).
great way to increase the risk of blowing your speakers

... if your amp has no speaker protection (incl. delay).
 

Online themadhippy

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Re: On / off switches
« Reply #12 on: May 20, 2022, 10:53:01 am »
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Would muting / disconnect circuits not protect the speakers
if fitted yes,but  isnt that common on professional equipment, muting if fitted is often only there to let the amp get stable and isnt long enough to let most digital mixing desks boot up.
 
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