Thread: Biggest machine you can have at a home that isnt yours?

My guesses are:
2.2kw on 10 amp circuit
3kw on a 15 amp circuit/plug (I've had an electrician install this on a rental property for me)
4kw on a 20 amp circuit/plug (will electricians install this with a power point? will most houses support it?)
100kw or whatever you want if you're prepared to buy a suitable 3 phase 415v diesel generator ?

I'm trying to work out what I can and can't run, particularly when it comes to smaller cnc machines that often require 3 servos around 1 kw and a spindle.

Are there any other things you can do, such as run a big tesla battery with a transformer and inverter?

No exactly what you are asking but strongly related.
If you know what you are doing you can run a 3Phase machines on a VFD on a smaller current rated GPO.

For example:
My Dust collector runs a 3kw motor and VFD on a 15A GPO 20A breaker but at 50Hz the max current draw at the GPO is around 9.6A continuous.
Same on my WW BS, around d 8.5A max.
Both of these could have their VFD programmed to not exceed 10A and hence be run on a 10A GPO (16A breaker).

I've also had a 4kW Compressor running on a VFD where the current never exceeded 14.8A - this was running on a 15A GPO with a 20A breaker.

Ah yes one of my mates runs his 3kw mill at less than 2kw on his residential 240v 10A supply with a VFD.

I was thinking more when you don't have the option to do that, when it's part of a larger system like a cnc one, and you want to use the existing electronics.

I am not sure but maybe there's a clever way of getting around it if you retrofit the machine with your own controls, like LinuxCNC (?). But most cnc mills and lathes require well over 2kw just to move their servos. Of course, with 3 1kw servos it may be very rare that you would run them all at full load - though servos can temporarily go over their rated power/amps, so it just gets trickier!

If I remember right, Ray G ran his 5-7hp 3 phase surface grinder off a VFD, and it only drew 7.5 amps on 240v

How many circuit breakers for power points do you have in the power box?
You likely have 2 for the house and 1 for the garage, i think i remember you saying it was under the house?
Anyhow if that is the case why not run a lead from the closest power point on a separate circuit
to run the cnc side of things.

shed

Originally Posted by shedhappens

How many circuit breakers for power points do you have in the power box?
You likely have 2 for the house and 1 for the garage, i think i remember you saying it was under the house?
Anyhow if that is the case why not run a lead from the closest power point on a separate circuit
to run the cnc side of things.

shed

Not quite sure what you mean, but I got a couple of questions which may relate.

Can you combine power somehow from 2 10 amp outlets? Connect them in parallel? I wonder what would happen.

Alternatively, could you run the servos with one 10 amp circuit and the spindle from another?
Maybe power the control stuff (24v) from a separate battery, using 18650s or the like?

I wonder what it would cost to get an inverter, transformer, and Tesla battery pack to try to produce 415v.

BaronJ are you around?

Yes i was sugesting that you locate and use 2 separate circiuts from your house, 1 to run the spindle and the other to run the cnc.
Save yourself some time and money trying to get 3ph with batteries ect and get one of those 220 to 380 v vfd's. I see bangood has them but i cant work out how to paste the link on my ph

Originally Posted by j3dprints

Not quite sure what you mean, but I got a couple of questions which may relate.

Can you combine power somehow from 2 10 amp outlets? Connect them in parallel? I wonder what would happen.

If the outlets were on the same circuit line you'd just blow the breaker when the breaker current was exceeded. This is as it should be as the breaker is there to protect the lines.

If they were on different circuits each with its own RCD, the RCDs might not like it.

If the two (say 10A) circuits were on the same RCD it would be like having a 20A circuit.

Originally Posted by j3dprints

Ah yes one of my mates runs his 3kw mill at less than 2kw on his residential 240v 10A supply with a VFD.

I was thinking more when you don't have the option to do that, when it's part of a larger system like a cnc one, and you want to use the existing electronics.

I am not sure but maybe there's a clever way of getting around it if you retrofit the machine with your own controls, like LinuxCNC (?). But most cnc mills and lathes require well over 2kw just to move their servos. Of course, with 3 1kw servos it may be very rare that you would run them all at full load - though servos can temporarily go over their rated power/amps, so it just gets trickier!

About the only easy/safe way you could get what you want is to get an electrician to run one or more 32A 240V circuits from the main board to a sub-board. Yep if it's a rental place you'd need owner permission and have to leave it all behind you. Depending on access for wire runs etc it shouldn't be all that expensive; I think the last time I bought some 6mm^2 cable (which is heavier than strictly needed for a relatively short run) it was less than $8/m. And sub-boards are cheap, even Bunnings has them these days.

I *think* most house connections are a minimum of 65A 240V which probably gives sufficient spare capacity but really I've no idea these days as both my houses have 415V 3 phase connections. I routinely use sub-boards to avoid big messy cable bundles and have breakers on both ends of the line so as to be able to totally isolate the entire sub-system.

PDW

Hi J3dprints, Guys,

I'm inclined to agree with PDW. A separate dedicated line that you can divide as needed at the machine end.

Here in the UK the older properties had 100 amp feeds, the newer ones only 80 amp and it seems that new ones are getting even less capacity.

I have a dedicated 30 amp feed for the workshop on 6 square mm, with its own breaker at the incoming supply end and a 8 way distribution box in the workshop. It runs though the roof space and then when it leaves the house goes underground the rest of the way then up on the inside of the workshop.

I wouldn’t bother trying to combine separate outlets.

I *think* most house connections are a minimum of 65A 240V which probably gives sufficient spare capacity

Older houses I would say yeah. Newer stuff well worth checking. Will use my own pers experience here. 2 lot subdivision I did a few years ago. Put in the paperwork with power auth and loaded up my list of power requirements for the newly created block (as you do!!). Long story short, you list what you would like to run off mains.

Was expecting to get 60amp. They came back with only 40!

Originally Posted by jatt

Older houses I would say yeah. Newer stuff well worth checking. Will use my own pers experience here. 2 lot subdivision I did a few years ago. Put in the paperwork with power auth and loaded up my list of power requirements for the newly created block (as you do!!). Long story short, you list what you would like to run off mains.

Was expecting to get 60amp. They came back with only 40!

40! I thought a friend of mine had it bad, he only has 45A single phase.

I've always gotten what I asked for - just told the electrician and that's the size of consumer main (house box to road) that got installed, then proper sized main breaker on the panel. Pretty sure my Sydney house is 16mm^2 and 65A per phase, Tasmanian place is 25mm^2 and 90A per phase.

Anyway a cable to a sub-board, appropriately sized and with proper breakers is the best way to do this. If the OP does a deal with the sparky to do the cable run that should bring the cost down a fair bit. Nobody really likes dragging cables through roof spaces or under house floors.

PDW

PDW

Originally Posted by j3dprints

My guesses are:
2.2kw on 10 amp circuit
3kw on a 15 amp circuit/plug (I've had an electrician install this on a rental property for me)
4kw on a 20 amp circuit/plug (will electricians install this with a power point? will most houses support it?)
100kw or whatever you want if you're prepared to buy a suitable 3 phase 415v diesel generator ?

I'm trying to work out what I can and can't run, particularly when it comes to smaller cnc machines that often require 3 servos around 1 kw and a spindle.

Are there any other things you can do, such as run a big tesla battery with a transformer and inverter?

Probably not much input though. Your asking what machines you can run at a rented property. Well that depends on what amps power is coming into the shed on the property and how flexible your landlord is. I agree with what you say in regards to the KW and circuit breaker size. I would say like a mig welder for example that some machines could be run on a lower amperage circuit breaker providing that there not running at full capacity. I remember having a Boss 200amp mig welder that the minium circuit size for 240V was 33.6A keep in mind that is for achieving the full duty cycle. I ran that welder plugged into a 15amp power point with a 20 amp circuit breaker and the wire size from the shed circuit board to the welders power point was 6mm2. I also had welder at full amps a few times and never had a problem.. Regarding what I've said though the start up current can be problem and trip circuit breakers. I know very little about VFD so I'm not going to comment on them.

Originally Posted by PDW

40! I thought a friend of mine had it bad, he only has 45A single phase.

I've always gotten what I asked for - just told the electrician and that's the size of consumer main (house box to road) that got installed, then proper sized main breaker on the panel. Pretty sure my Sydney house is 16mm^2 and 65A per phase, Tasmanian place is 25mm^2 and 90A per phase.

PDW

Where be your Tasmanian abode?

Originally Posted by Karl Robbers

Where be your Tasmanian abode?

South of Hobart. Send me a PM if you want to know in more detail.

PDW