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Currently adding a house extension which will have a roof lantern. I want to run a strip of WS2801 LEDs around the inner bottom edge to have some fun with (think "disco lantern"!). Electricians are currently on-site and I want to get the right cables in the walls.

I'll be using 2 x 5m reels meaning 320 leds. If I've understood the power needs correctly, WS2801 is about 60 milliamps per LED max meaning a 20amp supply should be enough. Is that right? I don't think they'll ever be all at full power but I want to allow for it as changing cabling later would be disruptive and expensive.

The power supply and controller are going to be in the corner of the room - about 5m away from the lantern in terms of cable run. I was considering running a small 2-core cable for data and then appropriate cable for power.

I have two questions about this. For the data - what is an appropriate cable? I've no idea what the issues may be around data loss over a 5m length. The controller will be small (Arduino or PI) so I could find a home for it up in the lantern, but I'd prefer to keep it more accessible if I can.

Regarding power - I'm expecting to need at least one connection per LED strip, more likely two. Question is, should I spur from a single power cable run to the base of the lantern (If I'm right about 20amp this should do) or am I better off running multiple, smaller cables direct from the power supply?

My electricians should be able to advise on this stuff I know but they've clearly not come across someone wanting to do something this ridiculous before and I'm getting blank faces from them.

thank you!

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  • \$\begingroup\$ You are definitely better off running multiple smaller cables to intermediate points; the strips themselves don't have great conductivity and if fed from one end only you can often see them fade towards the other end. There might be some electrical code considerations over using the same cable for low voltage DC, I don't know. \$\endgroup\$ – pjc50 Sep 27 '17 at 10:29
  • \$\begingroup\$ would you think it OK to spur a few smaller cables from a single 20amp cable run up to the ceiling though? Running multiple cables directly from the power supply through the walls seems a bit excessive. \$\endgroup\$ – Darren Miller Sep 28 '17 at 7:07
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After much deliberation with the electricians, have decided to put a 240v socket in he plasterboard up in the lantern well. I'll then build out a box to house a power supply and controller right next to the LEDS. Not ideal cosmetically but gives a lot more flexibility as to what I can install and also changing it in future.

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