Can I use an earth block as a bus bar?

Hi, I'm working on my boat's 12v electrics.

I bought this Bus bar recently for £11.50, and then came accross this Earth block for £1.50, which in theory seems to do the exact same thing, but it's smaller so it would fit better in my small electrical board in the cookpit.

Also, because I have 3 rooms on the boat (tiny bed room, cookpit, and small living room + kitchen), I need to buy 6 of these: a positive and a negative for each room. 6 times £11.50 is much more expensive than 6 times £1.50.

My question is simple: can I use this Earth block instead of the Bus bar, or is there any danger in doing so? The bus bas says it can take 100 Amp, while the earth block does not specify how much it can take. I know I will never use more than 30 Amps: fuses will ensure that. Also, I guess I would have to screw the earth block onto a piece of plastic; to insulate it.

Any thoughts?

Yes and yes to plastic or wood.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

You can use it as long as it is unearthed. Hence the plastic or wood mentioned earlier.

Thank you!

Someone told me that he thinks the earth block can take 60Amps-ish. As long as it's over 30A, that's great =) It means I can use it for domestic use (lights, charging laptop), etc. I will put a 30A fuse before that.

Wood as an insulator; great, thanks!