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I've bought some cheap AC-DC converter online. The goal is to place it inside a roof lamp's base, and power an ESP8266 clone at 3,3 volts from mains (in Europe, so 220v/50Hz). The lamp connection (mains AC) runs through the roof and walls to the mains , and I can't know the length. I don't know the material or section either, nor if it's braided or solid.

So. The final goal is to power an ESP8266 which would activate either a relay or a dimming circuit. Of course, the same wires would be used to power the light through the relay or dimmer.

On the AC-DC converter, the places to connect N and L lines from mains seem quite small. And so I was wondering what section of wire I could use from the AC to the AC-DC converter, so it'd be a few centimeters (or inches).

The specifications for the AC-DC converter are the following:

Input characteristics:

  1. Input current:0.065 (AC110V) -0.032 (AC220V) A (at full load conditions)
  2. Input surge current:20A (full load)
  3. Input voltage:AC 85-265v 50/60HZ (at full load conditions)

Output Characteristics:

  1. Output voltage:DC3.3V (±0.2V)
  2. Output current:1A
  3. Output efficiency:85% (rated load)
  4. Output ripple:50Mv
  5. Power:3.5W
  6. Size:5.1*2.3*2.2(cm)
  7. Ambient temperature:-20 to 60 Centgrade
  8. Relative humidity:40 to 90% RH
  9. Switch overshoot:150%
  10. Output rise time:100MS

Picture of the AC-DC converter

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  • \$\begingroup\$ To meet compliance or just not cause a fire? \$\endgroup\$ – winny Sep 19 '16 at 8:10
  • \$\begingroup\$ @winny well, to have a VERY high confidence it'll never catch fire... \$\endgroup\$ – ThaNerd Sep 19 '16 at 8:12
  • \$\begingroup\$ Your average H03VVH2-F should do the job. \$\endgroup\$ – winny Sep 19 '16 at 8:24
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This is a small load. Just use ordinary 1mm cable as used for the standard lighting circuit. The surge is irrelevant in this situation. Make sure all your connections are sound and safe. Also be aware that depending on how the lighting circuit is wired, you may not have a permanent live there, just a switched live from the switch.

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  • \$\begingroup\$ I'm aware of that issue, it's the same for my commercial light bulbs (Philips Hue)... \$\endgroup\$ – ThaNerd Sep 19 '16 at 12:50
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Be aware of the fact that you are working with 230V mains. If you are not sure about safety stay away from it. Since your lamp already has a mains connection it is most probably wired through a switch and 1.5 mm2 or 2.5 mm2. A good and at the same time safe way of completing your exercise is to place a double outlet at the position of the lamp using the already present wiring. From there you can connect your AC-DC converter well enclosed with a short wire and plug. Twin wire 2 x 1mm2 will do. The other outlet you can use again to realise a new supply to your lamp with whatever you want to put in between. The 20A surge current does not form a ploblem since this current only flows a very short instance (startup.

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  • \$\begingroup\$ I'm more used to DC than to AC, but I don't think there's much risk. It's not a plug that's coming from the roof but plain wires. The reference given by @winny refers to 2x0.75mm, I think I'll take a strong power cable (the kind used to plug a computer supply to power outlet) and cut a few centimetres. Additionally, I'll perform pre-testing of my whole circuit with an old lamp which I can access easily before I mount it all to the roof. \$\endgroup\$ – ThaNerd Sep 19 '16 at 12:48

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