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I purchased a split core current transformer (SCT013 30A / 1V) and I want to make sure I don't need to install a burden resistor. The attached picture shows the guts of the transformer. Isn't the piece labeled '8ZRO' a burden resistor?

guts of transformer

enter image description here

enter image description here

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    \$\begingroup\$ That's probably 82R0 meaning 82 Ω (the R serves as the decimal separator). \$\endgroup\$
    – JYelton
    Commented Feb 21, 2023 at 18:12
  • \$\begingroup\$ Please list the full part number for the device because that will tell you whether it has an internal burden resistor. In other words, if your device is a SCT013-030-30A-0-1V then it will have an internal resistor. \$\endgroup\$
    – Andy aka
    Commented Feb 21, 2023 at 18:33
  • \$\begingroup\$ @Andyaka Thanks for the idea, but I don't see any other identification on the item other than what I uploaded in the second image. \$\endgroup\$
    – Steve Cerullo
    Commented Feb 21, 2023 at 19:16
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    \$\begingroup\$ definitely a burden resistor already populated \$\endgroup\$
    – BeB00
    Commented Feb 21, 2023 at 19:27
  • \$\begingroup\$ The problem I see it is that it's possibly a fake part. I believe the original part is made by YHDC and your product has, what looks to be a fake logo i.e. it says YHDO. I'm not 100% about this of course. As with any device you may wish to buy it has to be from a reputable source and have a data sheet. The nearest I can find is tinytronics and, it does have a data sheet on that page. Anyway, long story shortened is that I recommend you find a data sheet. \$\endgroup\$
    – Andy aka
    Commented Feb 21, 2023 at 19:38

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It is labelled 30A/V, so for that to be accurate it must have an internal burden resistor, to convert the current into a voltage (as indeed is shown in photo).

A current transformer without a burden resistor would be labelled something like 100A/5A. And this does then require an external resistor.

Be aware that with an unburdened CT the output wires must never be left open circuit under load (very high voltages will be developed).

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  • \$\begingroup\$ You can see the difference called out in the penultimate line of the included spec sheet, where it says "voltage output built-in the sampling resistor" \$\endgroup\$
    – colintd
    Commented Feb 21, 2023 at 21:45
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    \$\begingroup\$ I dont think high currents will develop - the whole point is that the current is proportional to the current in the wire - if the wire current is 30A, and the turns ratio is 1:1800, then the maximum current in the CT is 17mA, regardless of what the resistance is (even if its shorted). The potential danger is only the high voltage \$\endgroup\$
    – BeB00
    Commented Feb 22, 2023 at 2:32
  • \$\begingroup\$ You are if course right. The dangers of late night answers. Thanks, I'll correct. \$\endgroup\$
    – colintd
    Commented Feb 22, 2023 at 8:11

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