Use CAT5e or CAT6 cable to Extend RS485 cable from Meter to Inverter?

[ChrisJEvans]

Can I use CAT5e or CAT6 cable for a short extension of the RS485 cable from Meter to Inverter?

The included 5m cable with my new Solis inverter needs to be extend by about 8m. The inverters meter has a clamp so must be near the main meter and the inverter is in the loft.
I know RS485 should be screened but on such comparatively short run might it work?

The CAT5e & CAT6 cable I have is unscreened

Also what is considered the best way to physically connect the extension to the supplied cable, it ends in two separate prongs.
I realise most connectors wouldn't let the twist every ? cms to happen.

Strangely the Solis inverter comes with an RJ45 coupler which would allow easy extension of the batteries CAN cable but surely that would be very rare given how difficult extending the DC cable would be!

[Oldgreybeard]

Yes, it will be fine out to about 100ft. Just use one of the twisted pairs and ignore the rest, or join all the spares together and use them as a screen. Soldered joints and heatshrink sleeving is the neatest and most robust way to make the joints, I think, but RS485 is pretty tolerant.

[marshman]

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[MrPablo]

Interesting, my Solis came with an Acrel meter that has a RJ45 socket on the bottom. It was easy for me to put the meter in a separate enclosure by the CU, clip the CT around the live trail and then CAT5e back to the garage inverter.

I'm guessing you were supplied with a different meter, perhaps an Eastron unit?

[ChrisJEvans]

Yes it is an Estron SDM120CT.

Thanks for all the pointers they all sound good and fairly easy to do.

I have realised there is an alternative: Our power is overhead so I can fit the clamp to the power cable in the loft within 5m of the inverter.
I think clamps are Normally fitted after the meter but I can't see being before a problem.
I do though need to power the meter. There just happens to be a 13Amp socket in the loft any reason why I can't use that?
Fitting a fused spur to that circuit does seem a bit of overkill.

[ChrisJEvans]

Doh! I think I was being stupid about putting the clamp on the power cable in the loft. The cable is combined Live and Neutral and I believe clamps have to be round only the live cable? Is that correct?

[Oldgreybeard]

Doh! I think I was being stupid about putting the clamp on the power cable in the loft. The cable is combined Live and Neutral and I believe clamps have to be round only the live cable? Is that correct?

Yes, just around the live tail, or the neutral tail (they should both carry exactly the same current, although in different directions).

[ChrisJEvans]

Thanks that makes perfect sense.