Is this wiring safe for Pixcon16?

[WeissWelsh]

Hello,

I'm not exactly great with electrical wiring. Can someone look at the attached photo and tell me if this is safe? I'm wiring two Pixcon16 boards with four 12V Power Supplies. I randomly chose colors for the picture, so ignore the incorrect coloring. My main question is whether or not I can daisy chain all the power supplies together like the picture shows even though they are going to two different Pixcon16 boards. Will that affect the Pixcon16 normal operation in any way? Are the two Pixcon16 boards separated properly?

Thanks for your help

Bob

[TheDucks]

If those are 300W supplies, you are nearing the edge of a single 15A (14ga cord)) derated 

I would put a bond wire between the Negatives of each PAIR (on same PIXCON)b PSU

 

[k6ccc]

I'll bite my tongue on the colors   You're fine.

 

[WeissWelsh]

2 hours ago, TheDucks said:

If those are 300W supplies, you are nearing the edge of a single 15A (14ga cord)) derated 

I would put a bond wire between the Negatives of each PAIR (on same PIXCON)b PSU

They are 360W power supplies, which I think comes to 3A each on 120V. So that would make it 12A for all 4. Is that too close for a 15A circuit?

I'm not sure what you mean by "bond wire." Sorry, I'm really new to this. Do you mean connect a wire to a negative terminal on one power supply to a negative terminal on the other power supply (the two power supplies feeding one Pixcon16?) 

[WeissWelsh]

2 hours ago, k6ccc said:

I'll bite my tongue on the colors   You're fine.

I knew that would drive you crazy. ?

[dibblejr]

1 minute ago, WeissWelsh said:

They are 360W power supplies, which I think comes to 3A each on 120V. So that would make it 12A for all 4. Is that too close for a 15A circuit?

I'm not sure what you mean by "bond wire." Sorry, I'm really new to this. Do you mean connect a wire to a negative terminal on one power supply to a negative terminal on the other power supply (the two power supplies feeding one Pixcon16?) 

I bond my grounds together.

If you search you will find a pic of what I am referring to.

Also why do you want to tie all 4 into one 120v power source?

I use 2 ps's each or one large ps. But I have pixie16's that does not matter just throwing that out there. Wiring is the same.

JR

[k6ccc]

5 minutes ago, WeissWelsh said:

They are 360W power supplies, which I think comes to 3A each on 120V. So that would make it 12A for all 4. Is that too close for a 15A circuit?

It's pretty much maxing out a 15A outlet.  Your 3A each is assuming 100% efficient power supplies which is never the case.  Assuming that it is the only stuff on a 20A circuit, and you use a large enough extension cord (or cords) if needed, you would be OK.  On the other hand, we're assuming worst case situation of all pixels on full white which is also seldom the case.

13 minutes ago, WeissWelsh said:

I'm not sure what you mean by "bond wire." Sorry, I'm really new to this. Do you mean connect a wire to a negative terminal on one power supply to a negative terminal on the other power supply (the two power supplies feeding one Pixcon16?) 

That is exactly what it means. 

 

[WeissWelsh]

28 minutes ago, k6ccc said:

Assuming that it is the only stuff on a 20A circuit, and you use a large enough extension cord (or cords) if needed, you would be OK

I do have a few 20A circuits available. We had a subpanel put in awhile back. Most of the breakers are 15A. However, there are three 20A circuit breakers in the subpanel, each going to 20A receptacles using 12g wire. If I use a 12g extension cord from one of those receptacles to the 4 power supplies, will that be sufficient?

 

[WeissWelsh]

48 minutes ago, dibblejr said:

I bond my grounds together.

If you search you will find a pic of what I am referring to.

In the picture I uploaded, aren't the grounds already bonded together? All the grounds are connected together. Is that what you mean?

[k6ccc]

1 minute ago, WeissWelsh said:

I do have a few 20A circuits available. We had a subpanel put in awhile back. Most of the breakers are 15A. However, there are three 20A circuit breakers in the subpanel, each going to 20A receptacles using 12g wire. If I use a 12g extension cord from one of those receptacles to the 4 power supplies, will that be sufficient?

Yes, that would be better.  Note that whatever you use for multiple outlets at the end of the extension cord needs to be rated.  A lot of plug strips are not.

 

 

[WeissWelsh]

11 minutes ago, k6ccc said:

Note that whatever you use for multiple outlets at the end of the extension cord needs to be rated.  A lot of plug strips are not.

OK..... This may be totally stupid, so forgive my ignorance. What I had planned to do was to buy a small 2-foot 12-gauge 3-pronged extension cable. I was going to cut off the female end and connect those wires to the input terminals on Power Supply #1. Then I was going to connect those exact same terminals on Power Supply #1 to the input terminals on Power Supply #2. Then connect those same input terminals on Power Supply #2 to the input terminals to Power Supply #3...... then do the same thing from #3 to #4. Does that work fine or is there something in your head screaming "This guy is insane."    

Oh, the male end of the 2-foot 12-gauge 3-pronged extension cable would plug into a 12gauge extension cord from the 20A receptacle. 

 

Edited September 20, 2017 by WeissWelsh

[k6ccc]

That would work, but it would make repairs far more difficult.  Better yet, cut the female end of your extension cord off and install a quad box with four outlets.  Then plug four short cables from the power supplies to the quad box.  that would make it far easier to repair in the middle of your show when a power supply fails.

16 minutes ago, WeissWelsh said:

In the picture I uploaded, aren't the grounds already bonded together? All the grounds are connected together. Is that what you mean?

Yoe your drawing does show the grounds together.  However, confusion on use of the word "ground".  I'm pretty sure he is talking about bonding the negative of each power supply together.  Although on MOST pixel controllers that have dual inputs, both negatives are tied together on the PC board, it's not a bad idea to tie them together at the power supply end.

 

[dibblejr]

1 hour ago, WeissWelsh said:

In the picture I uploaded, aren't the grounds already bonded together? All the grounds are connected together. Is that what you mean?

No, on each PS I bond (make a short jumper wire) and I connect one end t V- and the other to the ground, I was taught this in model railroading. So for 2 ps's I have 2 jumpers. (one on each). There may not be a dif with your setup

[TheDucks]

3 hours ago, WeissWelsh said:

They are 360W power supplies, which I think comes to 3A each on 120V. So that would make it 12A for all 4. Is that too close for a 15A circuit?

I'm not sure what you mean by "bond wire." Sorry, I'm really new to this. Do you mean connect a wire to a negative terminal on one power supply to a negative terminal on the other power supply (the two power supplies feeding one Pixcon16?) 

Yes, that is too tight if you arem running those hard. The 80% rule is to avoid heat buildup in the wiring (this includes your House) If ANY plug runs hot to the touch, it is overloaded or making poor contact. If you have Aluminum House wire and this happens: GET AN ELECTRICIAN before your house burns. Aluminum develops oxides that make joints POOR, thus heating under mild loads.

80% rule applies to loads of 4 hours or more at or above the limit. 12A is the tops for a NEMA 5-15P. (who knows what your outlet is really like inside. A cheap GE outlet failed: it was a slim slot in a sheet of brass colored metal. That was all that made contact with the wide blade of the plug. .065" ) Contractors grade have flats touching the blades. Others are somewhere in between

15A is 12A continuous, 20A is 16A continuous. Then there is the voltage drop on the extension. 16Ga is common. 14 or 12ga is EXPENSIVE. You should also bump the gauge for every 50' (16 becomes 14, 14 becomes 12 )

These are Switch mode supplies. They are constant power (for a given load) Pin= I*E. If E goes down due to voltage drop. I goes UP

 

bond. Yes that means a jumper (18Ga is fine. it is not handling current, only making the EM noise reference equal)  I tend to do 'best practice', being a semi-retired Electronics tech

 

[WeissWelsh]

On 9/20/2017 at 12:28 PM, TheDucks said:

I would put a bond wire between the Negatives of each PAIR (on same PIXCON)b PSU

 

On 9/20/2017 at 5:34 PM, dibblejr said:

No, on each PS I bond (make a short jumper wire) and I connect one end t V- and the other to the ground

It sounds like there are two things going on here. If I'm reading this correctly, TheDucks suggested putting a bond wire Between a V- terminal of one power supply to a  V- terminal of the other power supply. Also, Dibblerjr suggested putting a bond wire between the Ground terminal and a V- of the same power supply (and do the same to the other power supply.). My question is this: Are both of those suggestions needed or does one make the other redundant?

 

Bob

[TheDucks]

1 hour ago, WeissWelsh said:

 

It sounds like there are two things going on here. If I'm reading this correctly, TheDucks suggested putting a bond wire Between a V- terminal of one power supply to a  V- terminal of the other power supply. Also, Dibblerjr suggested putting a bond wire between the Ground terminal and a V- of the same power supply (and do the same to the other power supply.). My question is this: Are both of those suggestions needed or does one make the other redundant?

 

Bob

The between makes sure that the PSU's use the same level for the return (V-)

I suspect that the Earthing of V- is done with capacitors to reduce (EMI) noise.

Not everyone wants V- to be at Earth level (Positive Earthed systems) 

In this case, it probably does not matter.

We all assume the Green wire IS connected to a Functional grounding outlet

[WeissWelsh]

6 hours ago, TheDucks said:

The between makes sure that the PSU's use the same level for the return (V-)

I suspect that the Earthing of V- is done with capacitors to reduce (EMI) noise.

Not everyone wants V- to be at Earth level (Positive Earthed systems) 

In this case, it probably does not matter.

We all assume the Green wire IS connected to a Functional grounding outlet

Thanks so much. That's exactly what I needed to know. I apologize for all the questions, but I wanted to be sure I didn't blow anything up when I turn all this on for the first time. :-)