3 Phase 380/415, 32A vs 63A?

[Mrdjc]

Hi there,

We're planning on renewing the electricity in an old building in Slovakia, as currently it is fed with TN-C-S, but the PE isn't actually split off inside the house, instead in every socket the PE is connected directly up to the N, and most of the wiring is aluminium dating back 50 years or so.

In other words, the whole lot is getting renewed.

The supply is in 3 phase 380/415, and currently there is an old 3 phase socket in the workshop which is used very rarely for a large pump, or circular sawbench etc. However the old supply cable is aluminium, no idea of which size conductor, and also only 4 core, so no PE again.

We want to replace this as well, however should I go for adequate cable for a 5 pin 63A socket or should I just go for a 32A socket? I have no idea of the amperage of the devices that get hung onto it from time to time, the whole supply into the house is fused with a 63A fuse, over 10mm2 4 core (The new cable the electrician has supplied).

Any suggestions as to whether is its worth my while (and money!) to spend more to get a 63A socket set up with 10mm2 5core capable of taking 81A according to the data sheet

Or should I just stick to 4mm2 5 core capable of taking 49A according to the data sheet, and stick a 32A socket on the wall?

Realistically speaking, for domestic use isn't 3phase 63A overkill?

 

[Space cat]

I have no idea of the amperage of the devices that get hung onto it from time to time

Then you need to find out because that will answer your question. You can't design something if you don't know what it has to do.

 

[Mrdjc]

I'd be lucky to find a information plate on any of those devices!
They are probably 1960's soviet built hulks.

It's very annoying as its rarely used, but it seems like a shame to get rid of it all together.

How many devices do you know (in a domestic environment) which demand 63A 3 phase? I can't think of any..

*edit* I just went off on a hunt on ebay, I can't find ANY devices that want 63A in 415V, they are all 32 and below..

32A it is

 

[Space cat]

How many devices do you know (in a domestic environment) which demand 63A 3 phase?

That kind of power is almost enough to run a particle accelerator! (You'll also need a basement with a two foot thick concrete roof slab. )

The simple answer to your question is "none". You might just want three phase power for something with a big motor in it - like a lathe. If I remember, I'll ask my friend in the mechanical workshop tomorrow how many amps a modest sized lathe needs.

Edit: I just read your edit. No atom smashers for you then.

 

[Mrdjc]

Thank you very much for your reply, it's good to have my suspicions confirmed.

I've just started playing with the voltage drop calculator on TLC and according to it I can hang 6KW @ 230V & 12KW @ 415V on it. (25M run of 5core 4mm2)

Other than a huge immersion heater I can't possibly imagine what would want that kind of oomph. I'd imagine that anything that wants that kind of power would come with its own diesel or petrol engine.

Thanks again!

Cheers,
Daniel.