[chas]

My controller chassis houses my Gecko's, Bob Campbell breakout
board, and solid state relays and all is grounded to earth ground
from my 110ac line. The power supply however is in another
chassis and the output is isolated from the imput, therefore
when I connect the ground from the power supply to the
Gecko's (term 1) it will not be connected to earth ground from
the 110ac line. Will this cause a problem??

[chas]

I really want to power up my controller this weekend, and don't
want to see a puff of smoke!!!
I connected the (-) from the power supply to (term 1) of my
Gecko's. I also connected the (-) from the power supply to
my earth ground from the ac line.
Please! Please! can anyone see a possible problem with this!
Thanks
Chas

[Al_The_Man]

Generally it is desirable to have all the power supply commons at ground potential and if the power supplies are all initially isolated it is considered safe to make them common ground, a test to see if commoning up will cause any significant problems is to do a test to see if doing so will cause a large leakage current to flow, measure the voltage both DC and AC from the supply common you wish to ground and the actual ground, you may see a voltage with a sensitive meter due to natural leakage, which is normal, while the meter is connected place a 100ohm resistor across the meter leads an see of any leakage voltage collapses, if it does, then you should be ok to common up.
Al

[lerman]

Generally it is desirable to have all the power supply commons at ground potential and if the power supplies are all initially isolated it is considered safe to make them common ground, a test to see if commoning up will cause any significant problems is to do a test to see if doing so will cause a large leakage current to flow, measure the voltage both DC and AC from the supply common you wish to ground and the actual ground, you may see a voltage with a sensitive meter due to natural leakage, which is normal, while the meter is connected place a 100ohm resistor across the meter leads an see of any leakage voltage collapses, if it does, then you should be ok to common up.
Al

Al, you left out the part that says: if the 100 ohm resistor vaporizes, it is NOT ok to common up.

Ken

[Al_The_Man]

Al, you left out the part that says: if the 100 ohm resistor vaporizes, it is NOT ok to common up.
Ken

I took that as read...
Actually, only 1 amp would flow if the difference was 110vac, but you would need a high wattage resistor to prevent vaporization :bat:
Al

[CJL5585]

Did you get the e-mail I sent.
Should answer questions.

Good luck,
Jerry