[chbot] Insulation Tester

Helmut Walle helmut.walle at gmail.com
Sun Jan 24 09:17:03 GMT 2021

There are regulations and mandatory standards specifying clearances and creepages for various
kinds of devices powered by low voltage (mains supply). For example, there are regulations and
standards covering this specifically for white-ware, and there are others for, e.g., electricity
meters. To make the designers' lives more interesting, and notwithstanding efforts to harmonise
globally, there are also some international differences and variations.

Kind regards,


On 24/01/2021 21:49, Richard Jones wrote:

> I'm no expert on insulation testing other than having designed Telco line interfaces years ago,
> so any comments on the test approach most welcome.
> For telco line interfaces we used to consider 5mm PCB gaps between copper tracks adequate
> insulation. These days I find that JLCPCB are quite happy to route air gaps between mains and
> low voltage connections for no extra charge. So I design 1.5mm air gaps as well on a pcb routing
> layer. I view this as a much safer approach to give reasonable isolation even when things get
> damp and/or dirty.


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