How to use a plasma cutter on a first cut
Updated: October 2026
The machine is on the bench, the compressor is in the corner, and the first cut is not a race to 16 mm. This is how to use a plasma cutter on a 230/240 V garage inverter: earth on the keep-piece, dry air at the listed pressure, a visor you already own, then a slow edge start. It does not rank the four amazon.co.uk boxes. Gathered 19 October 2026. Peter F., the DIY & tools editor, did not cut plate in a lab. A qualifying purchase can earn a commission at no extra cost to you. The listings sit on the [plasma cutter comparison](/hub/cutting-tools/plasma-cutter).
The machine is on the bench, the compressor is in the corner, and the first cut is not a race to 16 mm.
The machine is on the bench, the compressor is in the corner, and the first cut is not a race to 16 mm. This is how to use a plasma cutter on a 230/240 V garage inverter: earth on the keep-piece, dry air at the listed pressure, a visor you already own, then a slow edge start. It does not rank the four amazon.co.uk boxes. Gathered 19 October 2026. Peter F., the DIY & tools editor, did not cut plate in a lab. A qualifying purchase can earn a commission at no extra cost to you. The listings sit on the plasma cutter comparison.
Our top picks
| Badge | Product | Start type | Torch | Air listed | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  SPRIGHOLLY SPRIGHOLLY CUT50L plasma cutter | HF non-contact | AG60, 4 m | 90 PSI, 60 L/min | 10.0 | about £67.83 | View offer |
| Best value |  Reboot Reboot 45 A plasma cutter | Pilot, non-touch | Pilot arc torch | Min. 6 bar / 90 PSI | 9.0 | about £103.67 | View offer |
| Alternative |  SPRIGHOLLY SPRIGHOLLY CUT50 contact plasma cutter | Contact / direct arc | PT31 | 0.4 MPa, 60 L/min | 6.4 | about £99.73 | View offer |
On this page
What is not in the box
None of these four cartons includes a compressor or a welding visor. The CUT50L, the contact CUT50, the Reboot 45 A and the CUT60L PRO ship as inverter, torch, earth lead and a small bag of nozzles. If the visor is still on a shopping list, stop. HSE WL15 names a welding visor, flame-resistant overalls and gloves. Plasma fume is a COSHH 2002 hazard. HSE says it has not been classed as carcinogenic and must still be controlled. Water-bath extraction in that note is factory plant, not a garage table.
Noise regulations use HSE action values of 80 dB(A) and 85 dB(A). An HSE note records plasma cutting up to 110 dB(A) at the operator. Hearing protection is your kit. Duty cycle is n/a on all four files. Do not invent 35% or 60% and cut until the case is hot.
Hook-up order for a 240 V garage cutter
Connect air first, while the machine is unplugged. Reboot prints a minimum of 6 bar / 90 PSI. The CUT50L prints 90 PSI and 60 L/min. The other two SPRIGHOLLY listings print 0.4 MPa, which is 4 bar. Set the regulator with air flowing. If the arc dies after a few centimetres, see the plasma cutter compressor page.
Earth the keep-piece, not the offcut, on bare metal. CUT50L and CUT60L PRO list a 3 m earth lead against a 4 m torch. Plug into a BS 1363 socket last and start the dial low. One CUT50L review flags a 13 A plug. One CUT50 review tripped a 10 A breaker. If the case smells of burning, the RCD trips, or the arc tracks through the torch, stop. A 16 A or 32 A outlet is an electrician's job.
Edge start, pierce, and the torch gap
Start at the edge when you can, so the arc sees daylight. A mid-plate pierce throws spatter back at the nozzle. Travel only after sparks leave the underside. Sparks that bounce back at the torch mean you are still skating.
The CUT50 is the contact machine: the tip may touch. The other three are written as pilot or non-touch. Jasic's UK guide talks about drag cutting at 40 A and below versus a 3–4 mm standoff. That is generic advice, not a licence to drag the AG60 tips. Reboot's distance guide is a reminder to keep that tip off the plate, not a 3 mm lab setting.
Too slow and the kerf widens. Too fast and the arc loses the bottom edge. The clean-cut lines here are 8–10 mm, not 16 mm. A first cut on 3–6 mm offcuts teaches the sound faster than a maximum coupon. Painted starts belong on the plasma cutter pilot arc page. Grind a bright earth patch even when the torch never touches.
After the cut
Air should keep flowing after you let go. That is post-flow. Only the CUT60L PRO prints a time: 2–15 s. Do not invent a figure for the Reboot or the contact CUT50. On the CUT50, let the screen turn off and the fan stop before you isolate the mains.
Drain the compressor and any filter bowl. A nozzle used as a drag tip on a non-touch torch will look oval; replace it before you blame the inverter. PT31 and AG60 consumables are not a universal fit. Structural and pressure-vessel work is not a first-week project. The next failure is usually water in the hose or a clamp on paint.
Common questions
What do I connect first: air, earth or mains?
Air first, while it is unplugged, then the earth clamp on bare metal on the keep-piece, then the torch, then the mains. None of the four prints an input current.
Where does the earth clamp go?
On the keep-piece, on bright metal. CUT50L and CUT60L PRO list a 3 m earth against a 4 m torch. Paint under the clamp is a false earth. Do not clamp the offcut.
Do I drag the tip or hold a gap?
Only the contact CUT50 is a touch start. The other three are written as non-touch. Jasic's drag advice is not a setting on these four. Do not drag the AG60 tips.
How do I know the plate has pierced?
Sparks leave the underside. If they bounce back at the nozzle, you have not broken through. Start at an edge when you can, and travel only after the underside opens.
Why does air keep flowing after I let go?
That is post-flow. Only the CUT60L PRO prints a time, 2–15 s. On the contact CUT50, wait until the fan stops before you isolate the mains.
When should I stop and call an electrician?
Stop if the case smells of burning, the RCD trips, or the arc tracks through the torch. A 16 A or 32 A outlet is an electrician's job, not a DIY socket swap.
Related pages
Sources
Public UK sources and the amazon.co.uk listings in this set, checked on 19 October 2026.
- HSE WL15: Welding fume (retrieved 19 October 2026)
- HSE: Cutting metals and similar fume (retrieved 19 October 2026)
- HSE: Noise (retrieved 19 October 2026)
- Control of Noise at Work Regulations 2005, regulation 7 (retrieved 19 October 2026)
- Electrical Equipment (Safety) Regulations 2016, regulation 35 (retrieved 19 October 2026)
- OPSS: Vevor plasma cutter CUT-40, 30 June 2023 (retrieved 19 October 2026)
- ESAB UK: Tips for buying a manual plasma cutter (retrieved 19 October 2026)
- R-Tech: Plasma cutting FAQs (retrieved 19 October 2026)