USB cables for power

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There are limits on the length of USB cables for data transmission but I want to use one only to supply power to a wifi connected CCTV camera. Anyone know if there is a limit on length for this purpose?
 
You'd need to know the reistance of the particular cable you intend to use. If you have or can borrow a multimeter with a reasonably sensitive ohmeter function it, it's a simple matter to measure the resistance and calculate the voltage drop over the run you need to use.

In the meantime, this page has some basic advice that might help: https://nerdtechy.com/usb-maximum-length
 
Good point. I do have a pretty good multimeter, problem is buying a USB cable long enough. I'll probably have to make my own.

Unfortunately it will all have to wait now anyway as just below where I was going to fix the cables, a pair of blue tits have decided, this afternoon, to start making a home in a little hole in my back porch.
 
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If you're making your own, you can reduce the resistance of the cable by using better wire. There'll still be some resistance but better/fatter wires will help a bit. Good plugs/sockets too.
 
There are limits on the length of USB cables for data transmission but I want to use one only to supply power to a wifi connected CCTV camera. Anyone know if there is a limit on length for this purpose?

As the data transfer of a USB is generally and typically limited to 5 meters, you will find that the USB cables are likely to be always up to a maximum of 5m, and very rarely over 5m, if at all.
 
Just a thought if you’re at all handy with a soldering iron or even with connector blocks. If it’s just DC power you want to connect for then get a short USB cable and chop it in half. Then get some suitable 2 core mains cable and use that to connect the +5V and GND wires by inserting it into the “chopped” bit. Should be far lower resistance than a USB cable and, while I can’t say how far you can run this, I’d expect it to be a far longer run than 5 or 10 metres.
 
Use a regular mains extension, plug a phone charger plug into and then run a short USB lead from that to the camera?
 
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