Anyone know about fuse / case requirements for mains-powered home electrical equipment (eg a fan) for the EU ? Specifically is a fuse required , case grounding required, any other main points?
Metal enclosures should be grounded with screw, switch should break both negative and positive line, fuse BEFORE switch.
Power and Standby Switches
Mains Power Switch
Every amp has a power switch. In fact, if you use a captive mains cable then you are supposed to include a power switch if you want to conform to UL/EN standards. It must switch both the live and neutral simultaneously (but the earth bond is never, never switched!).
If you use a detacheable mains cable (IEC lead or ‘kettle’ lead) then a power switch is not legally required. You can therefore use a single-pole switch if you want to, or even no switch at all (inconvenient!).
The power switch will need to be rated for use on mains voltage, and have sufficient current rating for the task. This should be no trouble; decent mains-rated switches are commonplace. Usually the switch is placed after the primary fuse, but this does not seem to be a legal requirement. A neon lamp is often added for power indication (optional, of course).
So uk devices seem to have fused plugs.
Electric devices in germany need an internal fuse if the internal circuit can not handle the power of the mains in case of short circuit.
So switchmode power supplys and transformers are fused to protect against melting switch transistors/rectifiers or short circuit in secondary winding (transformers).
There are a bunch of regulations.
Din vde0100 series in germany.
So as a rule of thumb use a fuse with 1.3 times current capability of the highest inrush current you expect.
E.g. transformer rectifier charging buffer capacitors while caps empty.
Think that fuses are temperature dependend.
Take internal wireing thick enough.
Grounding: all metal that can come in contact with ac mains by insulation failure needs to be grounded to protrctive earth.
Ground connections must not be part of mechanical construction but extra.
Ground screw just holds wire with eye nothing else.
Have contact washers that break oxide with screws.
Without ground you need “double insulation” which can withstand iirc 4kv.
Just look those things up, get number of standard and put it into ce papers if you want to sell a product. For hobby you can use my explanations and look it up to know about it.