Grounding Issue

Can the below be done safely? I have two circuits running 2 different sources.. space is limited and if I can get away with using a single ground that would be fantastic.

+120VAC-----------------|+ AC -----------------| LOAD | GND------| | -----------------|-DC +12VDC-------------------|+ LOAD
Reply to
none none
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I presume a bridge rectifier?

The answer is no... sparks will fly... you will be injured... don't do it.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

I doubt it. What voltage appears on the 12 volt output if the ground connection goes open circuit?

Reply to
John Popelish

Here is clarification for you on what i'm actually doing. I have a cold cathode light that runs off 120VAC, i have a inverter that converts 12VDC to the neccessary 120VAC.. i have an series of LED's that need DC.. so i was thinking of running the positive line for the DC power to the LED's then just hook the ground of the LED segment to the same ground as the return to the inverter.

"Jim Thomps>

Reply to
none none

ground

With respect to what?

Reply to
Richard Henry

With respect to the open circuit ground node. In other words, across the 12 volt load.

Reply to
John Popelish

Most small inverters (cigarette lighter deals) do not have a grounded (neutral) conductor. The center pin, typically the grounding conductor, may connect to the inverter case but nowhere else. I suppose you wouldn't hurt anything if you connected the inverter case to the DC ground and used that for your DC. That would be normal if it was installed in a car.You still would not have any connection to the AC side.

Reply to
gfretwell

Reply to
tooth

John, this circuit may or may not be done. What it really comes down to is if there are any other parts of the circuit that come into contact with each other. For example. If your just running a light from the 12v source then yeah, no problem. On the other hand, if the high voltage section is running an audio amp and the 12 volt end some other form of audio then it gets very complex but I would say 99% NO.

I don't know what your tying to pair together so let me know. If you really need to know what your doing just use your meter, the meter doesn't lie, you just have to know how to use it.

Seperatly power up both circuits and check with a volt meter between the grounds and see how much of a potentional difference there is. If there is 110 or some out rageous number then Hell NO, you can't do it. For audio purposes you may be able to fix this problem with a simple capacitor. TELL ME WHAT your doing.

The tooth. snipped-for-privacy@yahoo.com

Reply to
tooth

Sorry, I just saw your clairification. I'm not too familliar with inverters in terms of wheather or not they share a common ground. Doesn't matter, they really can't simply because the ac has to be created and you don't keep any ground in that type of circuit. What this means is most likely your ok. If I under stand what your doing. The Dc end and AC ends should have nothing to do with each other. You can always check first in both AC and DC for difference by meter first. I believe they are isolated thought. This is because on the DC end you have a + and a - and with no relation on the AC end you have a line and return. They are two different things in this case that because of the circuitry inbetween should be isolated and have no bering on each other.

Alway check with MR meter first, he doesn't lie.

Reply to
tooth

On Sun, 18 Jun 2006 02:16:55 +0000, none none top-posted:

If the input of the inverter, and the input of the +12 regulator, come from a single source, and the 120VAC is single-ended, then they should almost already have a common ground.

I see no problem, as long as you can safely ground one side of the 120VAC return.

If the grounding is done right, then the chances of it failing are almost negligible.

Slap one together on the bench, with a bunch of fuses, and see what happens! :-)

Good Luck! Rich

Reply to
Rich Grise

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