Very carefully confirming polarity

[Mike90250]

20mA Thru the heart is fatal. But not all amps are going through the heart, lots of other tissue in parallel paths. So 200mA might go hand - foot, but only a small portion thru the heart.

[SunEagle]

20mA Thru the heart is fatal. But not all amps are going through the heart, lots of other tissue in parallel paths. So 200mA might go hand - foot, but only a small portion thru the heart.

The problem is there is no guarantee that the current path does not go through the heart or what does is not dangerous to the individual. Better to be safe then sorry.

[max2k]

The problem is there is no guarantee that the current path does not go through the heart or what does is not dangerous to the individual. Better to be safe then sorry.

for the latter I use simple technique- when I need to work on array I turn AC disconnect (to prevent arch), DC disconnect and then I break the string somewhere in the middle by pulling apart MC4 connector. This break introduces resistance of several Gohm / tens of GOhm so even if any part of my poor body gets under voltage it will get: 400 * 10,000/1,000,000,000 ~ 4mV which is pretty safe by any account. Even if I have a leak of 1 MOhm and even ignoring the way leak current flows I'd get under 4V at worst, when for some unknown reasons I decide to touch both DC output string wires that are normally under 400V. Basically idea is to have 2 breaks- main DC disconnect + somewhere in the middle of the string in such a way you can't easily touch both ends of the second break. This way I can also work there in the normal day light hours any time I need.

[SunEagle]

for the latter I use simple technique- when I need to work on array I turn AC disconnect (to prevent arch), DC disconnect and then I break the string somewhere in the middle by pulling apart MC4 connector. This break introduces resistance of several Gohm / tens of GOhm so even if any part of my poor body gets under voltage it will get: 400 * 10,000/1,000,000,000 ~ 4mV which is pretty safe by any account. Even if I have a leak of 1 MOhm and even ignoring the way leak current flows I'd get under 4V at worst, when for some unknown reasons I decide to touch both DC output string wires that are normally under 400V. Basically idea is to have 2 breaks- main DC disconnect + somewhere in the middle of the string in such a way you can't easily touch both ends of the second break. This way I can also work there in the normal day light hours any time I need.

A pair of Class 00 600 volt gloves with leather coverings probably costs less than $100 and can be purchased from on line electrical safety product stores or even from Grainger if you want to spend a little more.