Are there any readily available CT clamps for the larger 4/0 (200A) service wires that are not $40 in the USA?
I see the options for shipping from China on ebay, just looking to get something a) faster and b) not $40.
EDIT: this is for an EmonTx
Hi WB,
Generally, no. But…
Sometimes you can snag Magnelab SCT-075 series CTs from eBay in the price range you’re
looking for. It’s a crapshoot, so you have to stay on top of it as they tend to sell fast at those
prices. Sometimes you’ll find them at the price you want, but the rating is at the wrong end
of the scale - usually too high. (e.g. 400 or 600 amps)
The main issue is they are almost always 333mV type CTs, you didn’t specify what you will
be attaching said CT to, so If you need a current output CT vice the voltage output type,
finding one at your price point with a wire window large enought to accomodate AWG 4\0 wires
becomes very difficult.
Thanks, Bill. I edited the post (it’s for an EmonTx). Does that influence your suggestions at all?
Yes, but unfortunately, in the wrong “direction.” You want CTs with current output vice
voltage output. That means finding one in your price range isn’t going to be easy without
resorting to buying them direct from China.
A 0.333 V c.t. is usable on an emonTx, but it’s far from ideal as, even when you’ve modified the emonTx by removing the burden resistors, it still uses only the bottom third of the input range, so your ability to measure small currents/powers is limited.
A current output type, i.e. a genuine current-to-current device, is far more versatile.