Products > Test Equipment
Power cables within test labs/your workbench?
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NickKUK:
I'm a beginner, but with the scope, power supplies, sig gen etc I'm starting to find my workbench has 8 power cables - 99% of them are 3 core (L/N/E). I've noted quite a noise at the mains 50Hz so I'm thinking putting the cables in a shielded box/conduit thus reducing the number of exposed mains cables but interested in what others do to minimise line noise?

Naturally shielded signalling cabling works well but I can't always operate in a closed metal box.

So what do you do to minimise the noise for your test equipment?
unknownparticle:
Where is the noise coming from?
NickKUK:
Sorry for the late response - the mad crush for December projects getting into production before the freezes and then COVID over the xmas and new year.

In short I believe this is due to having eight power blocks that are extension leads (plastic with non shielded cords) with the 2x SMPS, scope and sig gen all squirrelled into a corner, I also have the Mac mini and monitor close to that corner. LED main light.

I know the SDG1032X sig gen has phase noise and that seems to be riding on what seems to be gaussian noise with some periodic (I've been learning about clocks as I'm building my own) but given the Brymen 896s with leads can detect 50Hz mains in the air I suspect it's a case of shielding down the cables - either replacing the mains block with a shielded cable and shielded extension block or by slieving the mains cables for the instruments (or perhaps replace with after market shielded mains cables?).
jonpaul:
in 55 years of work as an EE with dozens of instruments and power cables randomly across my bench, never had the problem

I suspect your instrument is misconmected, not probing correctly or bad Chinese instruments CMRR

j
DavidKo:
How does your noise looks like? It is sometimes or still there?

It can be cell phone, wifi from your mac mini, bad switching power supply, LED lamp etc. Not like in old good days when it was usually from commutator motor without noise suppression (dead doggy capacitor was threw away without replacement).
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