Compressor power supply query

[Craig-SM]

OK, you clever people I am in need of your advice.

I currently have a Stanley 24ltr compressor and looking to get something a bit more capable. I have my eye on a Clarke 3hp 100ltr belt driven compressor and there in lies the problem.

The power supply into my garage is via 4mm armoured cable to 63amp RCD consumer unit with a 6A breaker for the lights and 16A breaker for the sockets. Both are on a ring. Most power hungry item is the 180A mig welder and a 30A plasma cutter.
If were to the 16A breaker for a 32A would I be able to run the 3hp compressor along with the plasma cutter. Nothing else on the circuits would be running at the same time other than a radio and the lights which are all LED and on a separate circuit?

 

[ChrisBailey]

I have a clarke se19c200. They recomend its wired upto a 40amp breaker as it will trip smaller breakers on startup.

You can run these things on 13amp plugs but its the startup that will cause problems.

 

[AVI_8]

If my memory is correct I think a 3hp compressor runs at 2200w which will draw just under 10 amps, though there will be a spike on startup
Ideally you’d want a 10mm swa in order to pull 40 amps from your combined equipment

 

[AVI_8]

That’s presuming you’re planning on running the compressor and plasma at the same time

 

[gaz1]

OK, you clever people I am in need of your advice.

I currently have a Stanley 24ltr compressor and looking to get something a bit more capable. I have my eye on a Clarke 3hp 100ltr belt driven compressor and there in lies the problem.

The power supply into my garage is via 4mm armoured cable to 63amp RCD consumer unit with a 6A breaker for the lights and 16A breaker for the sockets. Both are on a ring. Most power hungry item is the 180A mig welder and a 30A plasma cutter.
If were to the 16A breaker for a 32A would I be able to run the 3hp compressor along with the plasma cutter. Nothing else on the circuits would be running at the same time other than a radio and the lights which are all LED and on a separate circuit?

which 30a plasma cutter

you can run both but as i do but i stop when the compressor starts

this also allows a little cool down on the plasma cutter as well

my compressor is only a 40 litre though plenty ample enough at the moment ive already cut 5mm sheet and 3mm sheet steel no problem in that time

and im running that on a 2.5mm cable normally if i want a seperate supply id use an extension lead but mines the old type thick wire

 

[Craig-SM]

which 30a plasma cutter

you can run both but as i do but i stop when the compressor starts

this also allows a little cool down on the plasma cutter as well

my compressor is only a 40 litre though plenty ample enough at the moment ive already cut 5mm sheet and 3mm sheet steel no problem in that time

and im running that on a 2.5mm cable normally if i want a seperate supply id use an extension lead but mines the old type thick wire

It’s an R-tech P30C. My current compressor is enough to run this. It’s when I’m trying to spray anything it can’t keep up. A larger tank problem probably would be enough but if I’m changing I would like a bit more future proof.

 

[Craig-SM]

If my memory is correct I think a 3hp compressor runs at 2200w which will draw just under 10 amps, though there will be a spike on startup
Ideally you’d want a 10mm swa in order to pull 40 amps from your combined equipment

unlikely I would enough running at anytime to pull 40 amps as it tends to be one tool in use at anytime other than the plasma cutter that needs the compressor.

its the spike on start up that I heard about and was more concerned if that would be the problem and keep tripping the fuse making the compressor unworkable.

 

[AVI_8]

unlikely I would enough running at anytime to pull 40 amps as it tends to be one tool in use at anytime other than the plasma cutter that needs the compressor.

its the spike on start up that I heard about and was more concerned if that would be the problem and keep tripping the fuse making the compressor unworkable.

Use a C curve 32a breaker, it’s less likely to trip due to startup issues

 

[gaz1]

It’s an R-tech P30C. My current compressor is enough to run this. It’s when I’m trying to spray anything it can’t keep up. A larger tank problem probably would be enough but if I’m changing I would like a bit more future proof.

garage uses theres but after a while the tank gets a little hot for spraying as ive seen it used for under car spray and some panels

 

[MetalMonkey]

OK, you clever people I am in need of your advice.

I currently have a Stanley 24ltr compressor and looking to get something a bit more capable. I have my eye on a Clarke 3hp 100ltr belt driven compressor and there in lies the problem.

The power supply into my garage is via 4mm armoured cable to 63amp RCD consumer unit with a 6A breaker for the lights and 16A breaker for the sockets. Both are on a ring. Most power hungry item is the 180A mig welder and a 30A plasma cutter.
If were to the 16A breaker for a 32A would I be able to run the 3hp compressor along with the plasma cutter. Nothing else on the circuits would be running at the same time other than a radio and the lights which are all LED and on a separate circuit?

Just worth noting I'd expect the lighting circuit to be a radial, they normally are. 16A suggest the sockets might be as well, in which case you can't uprate the MCB.
Really you need to investigate before uprating an MCB anyway, there may be a good reason why it is derated.

3hp compressor on a 13A plugtop is never great anyway - in my experience they often blow, especially in colder weather.
Do you have enough space in the consumer unit to add in an extra MCB for your compressor? - That would be a much better solution, and put a dedicated 16A ceeform socket on it.

 

[carbon]

My current compressor is enough to run this. It’s when I’m trying to spray anything it can’t keep up. A larger tank problem probably would be enough but if I’m changing I would like a bit more future proof.

If you are trying to spray and are having problems then adding an additional or larger receiver will not help. The pump is the limiting factor here. If you have a spraygun that requires 9 cfm but your compressor can only supply 6 cfm then you may be able to spray small items before the pressure in the receiver drops and affects the spray pattern from the spraygun. For prolonged spraying the output of the compressor needs to be higher than the requirement of the spraygun.

 

[Edward Teach]

OK, you clever people I am in need of your advice.

I currently have a Stanley 24ltr compressor and looking to get something a bit more capable. I have my eye on a Clarke 3hp 100ltr belt driven compressor and there in lies the problem.

The power supply into my garage is via 4mm armoured cable to 63amp RCD consumer unit with a 6A breaker for the lights and 16A breaker for the sockets. Both are on a ring. Most power hungry item is the 180A mig welder and a 30A plasma cutter.
If were to the 16A breaker for a 32A would I be able to run the 3hp compressor along with the plasma cutter. Nothing else on the circuits would be running at the same time other than a radio and the lights which are all LED and on a separate circuit?

I ran my garage on a 6mm, down to 4mm half way along, 50ft long armour cable for 10 years, running a 3hp 150ltr compressor, 150amp mig, car ramp etc with no problems what so ever,
The CU was an old one, with a type of MCB fitted, it had never given me any problems running the compressor.

 

[AKN]

The size of the breaker is determined by the size of the cable it is protecting. According to the electrician who swapped out my consumer unit the 4mm cable to my garage could have a 32A breaker but no bigger.

 

[AVI_8]

As @MetalMonkey mentioned earlier, the op should check that the sockets are not on a radial, if they are it’s easy to convert that to a ring main, before adding the 32 amp breaker, if the plasma is pulling 30 amps it should be on its own dedicated 32 amp supply and ideally the welder at 180 should be on its own 16 amp supply though I know lots of folk run it from a 13 amp plug if not running at max power.
The limiting factor will be the 4mm SWA, it’s not rated for 40 Amps, 4 MM is I think rated between 30-37 amps for internal cable depending how its run (clipped direct or in conduit) and I think less if it’s a buried SWA. If you‘re doing it by the book that is.
My buried 10mm SWA is only rated for not much over 40 amps.

Also the OP should check what the supply cable is connected to at the house end, it could be a 16 or 20 amp mcb from the house CU

 

[Tim W]

I have a 3hp Clarke compressor, it runs on a 16amp mcb, "D" type. it ran fine on a "c" type until it got really cold then it trips all the time.
The previous owner used to run it on a 13 amp plug, never had a problem but it was in a heated garage next to a boiler, which helps

 

[Bornfree]

The size of the breaker is determined by the size of the cable it is protecting. According to the electrician who swapped out my consumer unit the 4mm cable to my garage could have a 32A breaker but no bigger.

Year's ago at the poultry factory I worked at, we had over the years added additional equipment so we started blowing the boards 375amp fuses . The engineer from Eastern electricity just felt the cable (it was quite hot) and he said "that's good for another 100amps" and he put in some 500amp ones and we never had another problem.