Grounding Antek power supply to equipment chassis?

[wlwoodall]

Hello all:

I have a 800W power supply purchased from Antek (PS-8N63). The power supply has two red wires (which goes to the neutral) and two black wires (which go to the hot) and is mounted on a large aluminum chassis. The DC output is on a green terminal board plainly labeled "+" and "-".

The heatsinked IC's are bolted to the aluminum frame. The problem is that the instructions make no mention of grounding. I have the incoming AC power cable coming in with a red, black and ground.

I connect the ac power cable red to the power supply red, the ac power cable black to the power supply black. I turned the power supply on and before just blindly connecting the ac power cable ground to the chassis, I measured the voltage difference between the ac power cable ground (still floating) and the chassis as follows:
ac power cable neutral (red) to aluminum chassis - 37VAC
ac power cable hot (black) to aluminum chassis - 55VAC
ac power cable ground (no connection anywhere) - 37VAC

Question: Do I just connect the the ac power cable ground to the aluminum chassis?

Bill

[lasik2025]

Bill,

Found the spec for your power supply at http://www.antekinc.com/details.php?p=282
Is this the correct supply ?

If it is, you dont HAVE to connect the AC wire earth ground but it is good practice to do so. Note that connecting the AC earth ground to the supply chassis will probably connect the - (minus) output of the 5v regulated to earth ground due to the Voltage regulator heat sinks connection (unless there is an insulator between the regulator and heat sink which is not visible in the picture on the web site).

Be safe.

Dave

[wlwoodall]

That is the correct spec. I only have the 63Vdc 12A output installed. Output 2 and 3 are separate modules which can be installed later. Useful if plans for other outputs are needed later. Also a fuse module is available but I didn't see that when I placed the original order so I didn't get that either.

That's one vote for connecting. Anyone else?

Thanks.
Bill

[Al_The_Man]

You should always connect the incoming service ground to your machine chassis, and preferably connect it or bond it to the common star Earth ground point in your enclosure.
It would be extremely bad practice if they used S.S. components, the body of which had a potential on them to ground.
The reason for your readings is leakage, inductive or capacitive from the incoming hot leads to the ungrounded chassis.
Al.

[buckeyes1997]

I have the same supply and left the green AC wire floating because I didnt want to fry the regulators. So you are saying that it should be tied to chassis? Have you done this yet and was there any problem with doing it? I certainly want my enclosure to be safe and not a shock hazard. I DO have a second module populated for 24VDC which doesnt have any components on the chassis. The main regulator board on mine does have the rectifiers component body tied to chassis though.

[Al_The_Man]

In order to ground equipment, you have to know what and how any of the electronics is referenced to chassis.
I would be extremely surprised if there was a potential on the chassis itself that was ABOVE referenced to ground, this would not only make it dangerous but make it impossible to earth ground the unit chassis.
It is possible, however unlikely, that the P.S. has the common side of the supply connected to chassis, in this case, there should be no problem of connecting the chassis to earth ground, and even if the P.S. is not directly referenced to chassis the common side could be taken to earth ground if you so wished.
The whole concept of grounding, bonding and commoning of supplies is very little understood.
Al.

[wlwoodall]

buckeye:

I did indeed take Al_The_Man's advice on 8-8-2010 and it has been working perfectly fine. The stray voltage went away and I've had about two hours of run time on it since.

Please reply back to this message and let us know how it went.

Bill