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Question on AC wires

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qtommer

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im doing a SMS Controlled Multi-Socket and i recently bought some wires to connect the LIVE contacts of the multi-socket to the relays on my PCB.

I haven't tested it out yet but id like to know whether what im about to do would be safe and feasible.

The only specs that the electronics shop could give me was that the cable had a rating of 600V.. So im assuming that the cable is good enough to withstand a voltage of 240V from the mains..? There was no current rating available..

Secondly, how should I attach this wires to my PCB? through a screw in socket or directly soldered to the PCB?


As for the connection to the LIVE contacts on the multi-socket, would soldering suffice?


Also, I would like to test my relay to see whether it is working so that when I input a voltage into the relay from my Circuit Board, the armature closes and lets the 240V pass through it...Other than connecting an appliance to the multi-socket to test whether the circuit works, is there any other "safer" way to validate that the 240V AC loop is closed?

Thanks
 
The current capacity of the wire is pretty obvious by it's thickness, how much current are you wanting anyway?. If in doubt, buy a piece of suitable capacity mains lead, and strip the individual wires out of it.

Soldering is fine, better than screwing.
 
I suspect the 600 V cable rating refers to the insulation resistance or dielectric property of the cable. At 600 V the insulation will start to be overcome and a catastrophic failure can lead to a short.

I might go with a little higher rating if it were me but for your voltage you will be within spec.
 
There are a few bits of knowledge needed to provide a good response for the cables.

First: How long of a run of cable will it be?
Reason: The longer a run of wire you use, the thicker in needs to be so carry the load farther. So the longer the run the thicker the cable. 600v cable can easy fall apart from 240v if the run was long enough. ALSO to consider, you can also lose some voltage if the cable is too big. If you run 12 volts through 4/0 cable at 3 feet you'll lose quite a bit of your current.

Second: Is this cable solid, or stranded, or coated
Reason: if the cable is solid it is more apt to hold up to switching and heat, however there is a larger amount of current loss though that huge chunk of copper. However if it is stranded it can melt easier with heavy loads, or inclement weather conditions, also more susceptible to corrosion.

Initial assessment: Currently it sound as if the wire will work for your application, however the variables list above can change this.

Optional assessment: Perhaps a smaller wire would serve better, less of a change of voltage loss, and probably easier to maneuver and handle
 
thank you all for your replies

Im actually going to connect these wires from the LIVE contacts of the multi-socket to my PCB so all in all it should be a wire length of less than a feet. As I am going to control 3 sockets of the multi-socket, hence there will be 3 pairs of AC voltage wires coming out from the socket to my PCB..

Will the PCB be strong enough to handle the voltage and current from the mains supply?

I actually do not know the actual current of the load required as the socket is to be used for various kinds of appliances and the current drawn would depend on the appliance connected to it.

As each of this socket will be controlled digitally by the microcontroller via relays, I would also want to be able to manually control the socket and I am thinking of using a pushbutton switch connected to the AC loop to achieve this..Will the pushbutton switches be able to handle the voltage and current as well??

thank u all for your help=)
 
There are a few bits of knowledge needed to provide a good response for the cables.

First: How long of a run of cable will it be?
Reason: The longer a run of wire you use, the thicker in needs to be so carry the load farther. So the longer the run the thicker the cable. 600v cable can easy fall apart from 240v if the run was long enough. ALSO to consider, you can also lose some voltage if the cable is too big. If you run 12 volts through 4/0 cable at 3 feet you'll lose quite a bit of your current.

Second: Is this cable solid, or stranded, or coated
Reason: if the cable is solid it is more apt to hold up to switching and heat, however there is a larger amount of current loss though that huge chunk of copper. However if it is stranded it can melt easier with heavy loads, or inclement weather conditions, also more susceptible to corrosion.

Initial assessment: Currently it sound as if the wire will work for your application, however the variables list above can change this.

Optional assessment: Perhaps a smaller wire would serve better, less of a change of voltage loss, and probably easier to maneuver and handle
" 600v cable can easy fall apart from 240v if the run was long enough. " got to call Bull Crap on this, 600v ratings are standard for use on 480v RMS because V peak of 480 approaches 600 volt. Bull Crap on this too. "If you run 12 volts through 4/0 cable at 3 feet you'll lose quite a bit of your current" you don't loose current, Electrons in = Electrons out. Sorry, I just disagree with most of this post.
 
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qtommer if you don't even know the current your load draws you're not even asking a question, we can't pull that information out of thin air and without it there's nothing to say.
 
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pardon me if im wrong but..

how do multi-socket manufacturers design the cables for their multi-sockets then?
They themselves dont even know the exact load of the appliance connected to it..as it varies from appliance to appliance

That is why when i mentioned that the load is not fixed, i'm assuming that someone would know the maximum possible current rating of the wires used in the industry for appliance multi-sockets.

thank you
 
As each of this socket will be controlled digitally by the microcontroller via relays, I would also want to be able to manually control the socket and I am thinking of using a pushbutton switch connected to the AC loop to achieve this..Will the pushbutton switches be able to handle the voltage and current as well??

Do ignore my question on the pushbutton as i have thought up an alternative safer solution.
 
will the PCB be able to withstand a current of 10A/240V?? ..
I noticed in another post similar to this that Nigel is obsessed about knowing the location of each poster.haha If it helps , Im from Malaysia.. (South East Asia)
 
will the PCB be able to withstand a current of 10A/240V?? ..
I noticed in another post similar to this that Nigel is obsessed about knowing the location of each poster.haha If it helps , Im from Malaysia.. (South East Asia)

With suitable copper yes it can (I have a PCB that carries 60A continuous with only a 20C temprise on the copper).
And location is important because suggestions on stockist can be made. There is no point me recommending to you Farnell to get electronic parts from if you are in Malaysia
 
on a PC board in one of my appliances, the solder blew out and arced around a relay pin, the first time, it musts have drawn an arc and burned the pin down to unusable, the next time, it just blew out the solder and left a black ring around the pin, so I scraped the green solder barrier and built a nice thick solder bridge around the pin. I recommend that each pin get a good solder bridge from the start. On commercial PCBs they use the wave solder method and I doubt it gives this extra amount of solder to help carry the current, plus it's tougher against vibration and cracking which would lead to arcing and burning around the pin.
2 cents
kinarfi
 
If in doubt use a jumper wire rated for the current you'll use then the PCB won't have to carry anything.
 
thank you all for your replies.. I have implemented all your advice into my PCB layout and will test it out tomorrow..
i have one final question..For each solder arcs that around the 240V pins, should I wrap it with some small rubber protective device? or is it okay to just expose it

thanks!
 
According to this site
PCB Trace Spacing for Voltage Levels
Your traces need to be about 1.5mm's apart. If you've met that spacing requirement there's no reason to put anything else over it unless you're worried about something getting nocked lose inside and shorting it.
 
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