32amp to 16amp single phase

[Lewis]

My plasma cutter came with a 16amp blue plug fitted which I promptly swapped for a 13amp plug so I could play with it straight away, however it absolutely loves to munch the 13amp fuses, especially when doing a lot of long cuts in quick succession.

We have 2x 32amp sockets wired through a 32amp breaker and then to a 32amp fuse in the board. Presently we've got a couple of leads made up with 32amp male 16amp female ends to run the massive Snap On battery charger/conditioner but I'm a bit wary of using the plasma cutter on these leads as the fuse is 32amp and presumably I could cause some damage to the machine before the fuse blows

I'm thinking of getting a secondhand consumer unit with a couple of 16amp C curve trips and wiring female 16amp sockets to these, so that the plasma cutter has it's own trip for protection. The consumer unit would be fitted with a short flylead and a 32amp male plug so that I could move it between either of the two existing 32amp sockets as needs dictate

So am I going way overboard trying to solve a problem that doesn't exist or am I on the right lines?

For reference the existing consumer unit is vintage and only has capacity for four fuses, all of which are in use. Power supply is 100amp single phase

[mickeyw]

When I bought my larger single phase MIG unit, it would keep knocking the trip out when starting a weld on full power. It came equipped with a 13A plug, the welder is 180A.

An electrician friend advised changing the trip in my garage from a B curve (normal domestic fiting) to a C curve item. That did the trick.

I suggest wiring a dedicated line to the consumer unit with a 32A C curve breaker. Fit a 16A socket on the wall securely, you don't want to be pulling on a flying leads from the consumer unit. Refit the 16A plug on the plasma cutter.

This is not OTT really, the parts aren't that expensive, and will give you reliable and safe service.

I also have my lathe's 4HP rotary phase converter wired to a 32A socket on a C curve trip. It runs very happily this way.

[Lewis]

I suggest wiring a dedicated line to the consumer unit with a 32A C curve breaker. Fit a 16A socket on the wall securely, you don't want to be pulling on a flying leads from the consumer unit. Refit the 16A plug on the plasma cutter.

I think you have misunderstood my requirements - I want to ensure the plasma cutter is fused adequately at 16amp, fitting a new 32amp breaker to replace the 32amp fuse would achieve little in this regard. Besides which the existing consumer unit cannot accept breakers - only Bakelite fuse holders with fuse wire. As its a rented building I don't want to replace the consumer unit with a larger more modern one. If I were to do as I outlined above the second consumer unit would be mounted on some ply with the 16amp outlets secured to this, the fly lead I mentioned would be to connect this second consumer unit to the existing 32amp socket outlet. Obviously I intend to refit the 16amp male plug to the plasma cutter

A cheap small consumer unit like this would do the job, but replace the 6amp and 16amp b curves with 16amp c curves, fit a single 16amp outlet to each of the mcb's and fit a 32amp male on say a metre of flex to plug into the existing 32amp fused outlets

[ChrisW70]

Yep, that would work fine, make sure your cable is suitably rated, I'd say 2.5mm for the 16A and 6mm for the 32amp.

The C type breakers have a higher tolerance to large inrush currents such as motors compared to the B type.

[miketomcat]

Or you could just buy a breaker that replaces the fuse they just push in instead of the fuse carrier.

Mike