Thanks for the replys. sounding like I've got the right idea at least in planning ahead and trying to learn as mich as possibel. Its just a very deep and winding rabbit hole that I'm in!

Now just neet to get to grips with some of the finer points in estimating the likely hazards etc.

My thinking on PPE at the minute is to have some Arc rated trousers and polo/tee shirt for day to day working with a boilersuit that I can put on over the top if the hazards are higher.

Has anyone any experience with gloves such as these: https://gsworkwear.com/products/portwest-arcgrip-gloves-a780?variant=15698900156459 I was thinking somthing like this for day to day working but wondered if they are really offering any worthwhile protecation?Then with gauntles if needed.

Plus the helmet, ear defenders, glasses, virsor as and when needed.

Out of interest, how much of an arc flash risk exisitis on an average domestic/light commercial installation when carrying out things like external earth loop impedance tests? I figured this is probably the highest risk as its at the cutout/main DB, live and with some exposed live parts. Obviously it varies with the exact installations but for something around 2kA prospective fault current with the standard DNO 80amp fuses for example, would you be looking at a a full gaultlets and visor set up to carry out that test, or would glasses, basic gloves and long sleves be reasonable protection.

Thanks

A crude worked example !

80A BS1361 fuse perhaps the ferraz shawmmut BME42V80

shows a total energy to open is 30,000 Amp² seconds.
We have to have a figure for the Zs of the supply, lets take a fairly bosky supply capable of a 230V open circuit and 20kA PSSC, so for the worst case, the energy into the fault and drop on the supply is equal, and 10,000A flows and 115V is dropped creating approx 1Megawatt of energy, but for how long before that fuse pops.
so the time is 30,000 divided by 10000A squared,(which is 100,000,000 A ²⁾ so the equivalent energy rectangular pulse duration would be ~ 1/3000 second (but course as the fuse 'blows' the current is not constant, but then neither is the switch off time a true knife edge). So worst case arc energy is the same as that megawatt for 1/3000 second , so about 3000 joules. Now if that was in free space, we would have to spread that over at least 600 square cm to get down to the "safe" (burnt bare skin, not that safe) limit, and that is actually not that large a sphere, about half a metre diameter or 25 cm ~ 10 inch radius. Redo the calc for 10 times the power density - about the "12 calorie" level for the overalls or thick gloves, divides the dangerous sphere diameter by about 3 (where 3 squared is almost 10) to  less that 10cm/ 4 inches But as above, the enclosure either saves you or could makes it 3 times worse depending where you are in relation to any focusing action.
This sort of wet finger sum only should be used to give a feel for how far back to stand ! There are a lot of approximations, and the 'formal standards grade' formulea are quite a bit more complex and nuanced...
Mike.

A crude worked example !

80A BS1361 fuse perhaps the ferraz shawmmut BME42V80

shows a total energy to open is 30,000 Amp² seconds.
We have to have a figure for the Zs of the supply, lets take a fairly bosky supply capable of a 230V open circuit and 20kA PSSC, so for the worst case, the energy into the fault and drop on the supply is equal, and 10,000A flows and 115V is dropped creating approx 1Megawatt of energy, but for how long before that fuse pops.
so the time is 30,000 divided by 10000A squared,(which is 100,000,000 A ²⁾ so the equivalent energy rectangular pulse duration would be ~ 1/3000 second (but course as the fuse 'blows' the current is not constant, but then neither is the switch off time a true knife edge). So worst case arc energy is the same as that megawatt for 1/3000 second , so about 3000 joules. Now if that was in free space, we would have to spread that over at least 600 square cm to get down to the "safe" (burnt bare skin, not that safe) limit, and that is actually not that large a sphere, about half a metre diameter or 25 cm ~ 10 inch radius. Redo the calc for 10 times the power density - about the "12 calorie" level for the overalls or thick gloves, divides the dangerous sphere diameter by about 3 (where 3 squared is almost 10) to  less that 10cm/ 4 inches But as above, the enclosure either saves you or could makes it 3 times worse depending where you are in relation to any focusing action.
This sort of wet finger sum only should be used to give a feel for how far back to stand ! There are a lot of approximations, and the 'formal standards grade' formulea are quite a bit more complex and nuanced...
Mike.