Choosing SSR and fuses for AC heatbed

Hi,
I am building a new printer with Silicone heating pad 220V, 750W, 300x300 mm.
[i.imgur.com]
I want to install it properly with all the safety precautions, because I don't want to kill myself or burn the house down.

Which solid state relay and fuses should I be using? Are there some detailed guides/wikis/tutorials on how to install all of it?
What types of wires/cables must be used?

Thanks!

Edited 2 time(s). Last edit at 01/02/2019 08:54AM by jjfawkes.

... think about using a transformator with 16V to 50V AC instead of direct line -- will reduce the possible hazards drastically!!

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Viktor, wouldn't it beat the whole purpose of having AC heatbed? If I underpower it drastically then it would heat at a similar speed as PCB or other types of DC regulated beds.

SSR: any DC-AC SSR with sufficient output voltage and current rating and with 3-32VDC control input is suitable. Current draw will be around 3.4A, but if you choose an SSR with a much higher current rating then you won't need a heatsink. Fotek SSR-25DA is a popular choice, although unfortunately many Fotek SSRs sold on eBay are fakes, with the triac inside rated at a lower current than it should be. Crydom D2425 is a more expensive alternative.

Cables: the silicon heater will probably come with a length of silicone covered mains cable already attached. The type of mains cable you need between the printer and the wall plug will depend on your local regulations.

Safety precautions:
- You must use a 3-pin plug and 3-core mains cable, and connect the bed plate and other metalwork of the printer to mains ground.
- For added safety use a GFCI (or RCD in the UK) protector in the mains supply.
- If the bed will be moving then use highly flexible cable to connect the bed heater wires to a terminal block on the fixed part of the printer, and you MUST use strain relief at both ends.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

... ich you already have a mains-heatbed, then go with it ... otherwise search one with lower voltage (eg. 12V or 24V) and drive it with slightly higher AC instead -- e.g. the 12V DC heatbed with 16V to 18V AC ... this will give pretty fast heatup times, compared to nominal DC

You can drive the DC beds with higher DC-voltages too, but the idea behind this "tweak" is to use cheap salvaged transformators instead of more costly high power PSU's ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

dc42 - thank you for the info, it is very useful !
Viktor - yes, I already have a 220V heating pad.