extending phone, camera power supply

[DrGonzo]

Is it possible to extend the cables that come with most phone chargers, IP cameras, etc.? These are the normally black cables connected to a step down ransformer.
They look like they just have 2 wires so could I just cut them and then wire them onto some standard wire with a connector point?
I need to feed some through a drill point in the wall so can;t simply use a plug extension.
Need to extend it by about 4m. The plug provides 5V, 1A

 

[Speakercon]

Fine from a safety aspect (as long as transformer is inside and the joints suitable made and protected).

However you may find a problem extending a 5V supply as the voltage drops very quickly over the cable. You might be ok for 4m, but I would check before installing. I needed to do a similar thing for a remote camera, I ended up running 12V to the camera location, then using a 5V DC step-down PSU located next to it.

 

[Taylortwocities]

However you may find a problem extending a 5V supply as the voltage drops very quickly over the cable.

Volt drop is a caused by CURRENT not VOLTAGE.

 

[Speakercon]

However you may find a problem extending a 5V supply as the voltage drops very quickly over the cable.

Volt drop is a caused by CURRENT not VOLTAGE.

Yes but I was just trying to explain briefly without going into lower voltage/higher current technicalities. It can be a problem extending 5V PSU cables because of the increased current and the fact the cable size is often very small resulting in high resistance.

 

[plugwash]

Volt drop is a caused by CURRENT not VOLTAGE.

The current causes the absoloute volt drop but the system voltage very much influences how important that resulting drop is. A volt drop of 2.5V in a 240V system is perfectly acceptable. A volt drop of 2.5V in a 5V system will almost certainly cause things to fail. Heck a drop of 0.5V may well cause things to fail.

We have to make some assumptions, in particular we don't know how much additional volt drop we can add before things fail so lets assume 0.1V. That means that the total added resistance (to both outward and return conductors) needs to be less than 0.1 Ohm. Looking at some figures from TLC I think with 1mm cable a 5m extension will probablly be fine.

Don't be tempted to use bell wire or similar.

Edit: fix quoting.

 

[bernardgreen]

[ so lets assume 0.1V. That means that the total added resistance (to both outward and return conductors) needs to be less than 0.1 Ohm.

if the current is 1 amp. with half an amp the added resistance could be 0.2 ohms and still only drop 0.1 volt

 

[TonyW2]

Would it not be simpler to extend the mains circuit to provide a socket?

 

[ericmark]

As already said much depends on the appliance and what volt drop it will work with however a 7805 voltage regulator to take 1A is a very cheap item and using a 9 volt supply and a regulator with good heat sink would likely do the job.

As to cutting leads not all power supplies have just two wires. By using 4 wires two supplying the power and two sensing the voltage one can run the supply over a very large distance with the power supply compensating for volt drop.

However since again 5 volt which is the voltage used with USB and there are USB chargers cheap 12 volt to 5 volt units to allow charging of phone etc in the car. So with a 12vdc supply one can reduce to 5vdc at point of use without needing to solder wires as would be needed with a 7805 voltage regulator. Although a LM7805CT is listed as £0.504 plus vat and rated at 2.2A and that's RS price likely you could find cheaper. 12vdc 1A power supply about £5 and a USB car charger £1 and socket to plug it into £1 for any of the pound shops as whole set-up unlikely to cost more than £7.

It may as said work by just extending a pair of cables but since there is no info as to what volt drop is permitted it's like asking length of piece of string. Yes I know since string runs down the centre of a cable then length of string is 185.2 meters but you know what I mean.

 

[seasickstevie]

We've got a wall-mounted phone in the kitchen, but I didn't want wires trailing to a wall-wart thingy, so I ran the CAT-5 from the bedroom phone socket above the kitchen (6 metre run). Plugged the psu in the bedroom. Cut the two-core mini-jack lead. Connected to spare cores in the CAT-5 and again in the kitchen the mini-jack that I'd cut off.
Plugged the phone in and voila!

Edited for spellung . . .

 

[bernardgreen]

You got a viola

Wow amazing what Cat 5 can do .

 

[seasickstevie]

Thank you Bernard

Viola / Voila

Easy mistake to make . . . I'm musically minded you see

 

[bernardgreen]

Noted

Cat5 or catgut strings

 

[ban-all-sheds]

The plug provides 5V, 1A

Just replace a few of your sockets with ones like these:

http://images.google.com/images?q=<usb+charger+socket>

 

[winston1]

The plug provides 5V, 1A

Just replace a few of your sockets with ones like these:

http://images.google.com/images?q=<usb+charger+socket>

Some of those look absolutely dangerous. 13A sockets with modified slots to take all manor of other plugs without fusing or shutters straight on a 32A ring main.

 

[ban-all-sheds]

Which ones are they?