I'm designing a transformer with some blades that I have EI and I have doubts about the current flow of the secondary. In the program I used, he canculated for each coil the AWG 15 wire that supports 4a, and how am I going to make a connection from one coil to the other to make the center tap, is it necessary to use an awg for example 12 or instead of awg 15?

Print from the program I'm using:

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Sorry for the ignorance, I've searched a lot about it, it seems silly to ask but I really wanted to know more about it.


1 Answer 1


Wire, connected to central tap, conduct current from 0A, in case the load is symmetrical, to 4A maximum. Keep the same wire size.

  • \$\begingroup\$ You could possibly make this a bit more clear for a chap from Brazil. It's a bit terse. \$\endgroup\$
    – Transistor
    Commented Sep 18, 2021 at 21:21
  • \$\begingroup\$ I'm sorry for this. but it was a doubt I had. Thanks for the answer. Actually I was like how am I going to ask that \$\endgroup\$ Commented Sep 18, 2021 at 22:13
  • 1
    \$\begingroup\$ @GabrielLSSaraiva, the answer is saying that if your load is perfectly balanced then there will be 0 A in the centre-tap and (if everything is perfect) you can use a fine wire. If there is a chance that the load is not balanced then you make the centre-tap big enough for the full current. Normal practice is to make all the wires the same size. \$\endgroup\$
    – Transistor
    Commented Sep 19, 2021 at 13:30

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