@swisstony Is the shed fed from a dedicated breaker in your house?
As it it only feeds the shed and not anything else in your home. Just wondering what it was used for before the electrician changed from 32A to 20A.
Edited to add: Just realised it feeds your garage!
[automerge]1585906289[/automerge]
Before going to the effort and expense of running another SWA cable you need to be realistic about what you plan on using in the sheds & garage to determine the load, and from there you can decide if the existing circuit and cable is acceptable or not.
Assuming the measured value of 0.21 is at the garage, and your cable is 22m long, then I estimate the resistance at around 0.63 ohms. That gives a 3% drop on 230V for around 11A.
The regs have 3% for lighting circuits due to the annoying flicker you see with filament bulbs which as quite voltage-sensitive, with LED lights you won't see as much effect. For other power circuits it is 5% drop, which would be 18A max.
So think about:
- What do you have in the garage using power?
- What do you plan for old shed?
- What do you plan for new shed?
Realistically if it is DIY style workshop with only you using stuff it will be one machine at a time, plus lighting, plus any electric heating (which might be the biggest load as 2kW is around 9A).