power cords

[sakone1]

what are the recommended input power cords? 2 prong or 3?

[memphislights]

I believe that the recommended cord for the outputs is 2 prong since there is no ground strap.

I think that input would most likely be a 3 prong due to the recommended wire gauge to handle the 15A max input current.  I am assuming that most people will use an old PC power cable for this.  I think that you just do not connect the green ground wire to anything, so you either heatshrink the end or cut it flush.

Others probably know better though.


Now that I am thinking about it, would there be any negative effects, other than cost to adding a grounding post for all of the power cords? 

[RJ]

I use three prong as said and cut off and shrink wrap the safety ground.  I never felt the extra ground was needed as the Lights themselfs do not have the ground plug.

RJ

[Greg]

memphislights,

PC power cords aren't anywhere close to heavy enough in my opinion.  Most are 18 gauge some are 16.  14 gauge is probably the minimum you should consider for 15 amps input current with occasional peak excursions toward 20 amps.  I used 12 gauge (which is good for 20 amps continuous) on the LEs I built this past year.

Greg

[memphislights]

Isn't the LE capable of dual AC inputs?  The 30A LOR systems are capable of dual power inputs and do use 14AWG for the input power cords and 18AWG for the outputs.  From what I have been reading, 14AWG is what is rated for 15A, but there is a caveat.  That rating is at 50C.  At lower temperatures, the safe current carrying capacity should be greater than at the rated "room temp".

On the other hand, almost everything that my friend is running is LED with the exception of a few incandescent items.

So at .03A per 50-60 ct LED string, and assuming a max working load current of 3A on each of the 6A triacs, that is around 100 strings per channel, and that is probably unlikely.  AT .3A per 100 ct incandescent, that is still 10 strings per channel, and I think that is probably unlikely as well.

So, assuming total amps at 30A for the unit, that would average out to around 2A per channel constant (60-70 LED strings or 5 incandescent strings per channel), but they probably won't be on constantly for long perionds of time.  You are only looking at a surge of 30A for probably less than a second, and that should trip your GFCI anyway.

I have plenty of the 18AWG to 14AWG PC power cords from PCS, servers, an monitors.  With ambient temps around 50F or lower during show times, this is only around 9C.  This should allow some additional overhead as far as conductor overheating.  This does not take into account any of the overhead that is built into the cable specs to begin with. 

All I am saying is that there is a perfect paper recommendation, but also a practical, safe, and less expensive  option as well.
I may still be wrong, but I will probably argue until my extension cord catches fire.


Oh, and if I am wrong about the dual AC input, then ignore what I just typed 

[Greg]

Yes the LEs are dual feed as designed, but I should think the majority of folks will use the LEs with the triac banks bridged as I did this past Christmas.

The most I pushed through any one of my LEs at any given time was about 25 amps for durations less than 30 seconds and a steady draw of just over 18 amps for several minutes at one point. The GFCIs I use are rated for 20 amps and are on dedicated 20 amp circuits with HACR type breakers.  I had no problems with GFCIs or breakers tripping.

At lower temps and more transient loading lighter wire may not be a problem for you.

If I hadn't had the heavier cords on hand, I might of used lighter wire and balanced up the loads more carefully across the controllers since 3 of them never exceeded an all on current of 6 amps for all 16 channels combined.

[memphislights]

It really does matter how much you want to run through the system.

Just a side note, the LE manual says to jumper with spt-2 16AWG (10A) to run with a single AC input.  Doesn't really matter in my case, but I thought it was interesting.

I am just cheap, and will use as much of the free stuff that I have one hand.

2x 18AWG, 2x 16AWG, or 1x 14AWG, should work fine unless you get too ambitious.

[ElectricCraft1]

Just from the electrical standpoint; the National Electric Code states that 15 amp is #14 wire, 20 amp is #12 wire, and anything over 20 amp to 30 amp is #10 wire.  Now, there are exceptions as to wire type, and can therefore change these ratings, but this is the electrical code requirements for sizing of wire.  If there are any questions, just let me know.  I check post every couple of days.

[ElectricCraft1]

I suggest using low voltage landscape wire.  It is rated for use outdoors, comes in the appropriate sizes, and is cheap.  Install your own 2 wire cord caps and you're done.

[ThaiWay]

^huh?

John

[memphislights]

I think that he is talking about using the SPT-1 or SPT-2 to make your output cords.

[ElectricCraft1]

Yes, your output cords can be low voltage landscape wire.  It is similar to lamp cord, but is rated for use outdoors and comes in the #12 size.  Landscape wire is available through many sources including Home Depot and Lowes.  Check You are not allowed to view links. Register or Login as well.  The cord cap is the female plug end that you can pick up at any hardware store for a couple of bucks.

[RJ]

Yes, your output cords can be low voltage landscape wire.  It is similar to lamp cord, but is rated for use outdoors and comes in the #12 size.  Landscape wire is available through many sources including Home Depot and Lowes.  Check You are not allowed to view links. Register or Login as well.  The cord cap is the female plug end that you can pick up at any hardware store for a couple of bucks.

I don't think we should be using wire rated at 12 volts to carry 120/240 volts. It is about the insulation as much as the size of the cable. If the wire is rated at 12 volts and not 120/240 the insulation is most likely not rated for the increased voltages.

The SPT wire that is rated for the highere voltages and can be bought from people Creative Displays can be bought cheaper so there really is no benifit to using the 12 volt cable that I can see.

Lets be safe and use the correct stuff.

Just a side note, the LE manual says to jumper with spt-2 16AWG (10A) to run with a single AC input.  Doesn't really matter in my case, but I thought it was interesting.

There are a few reasons this is fine on the LE.

first the jumper carries the load of 1/2 the board not the full load. So unless you overload or run the board way out of balance then you should be under 10 amps.

Second if you look at the Handbook of Electronic Tables and Formulas for American Wire Gauge. You will see that wire is rated under two uses.

1 - Transmission of power ( the normal use we have and what we quote all the time)
2 - Chassis wiring ( inside a case and a few inches at most, not bundled with other wires but open to air. Like in this use.)

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If you look up 16 awg you will see that for this use the wire is rated at 22 amps which is more than the whole LE is rated at with one feed. This should keep us well within ratings.

Hope this clears up some stuff.

RJ

[ElectricCraft1]

Yes, insulation is just as important as conductor size.  I am not going to argue, especially with the site administrator.  These units are qualified as a temporary installation therefore fall under a different section in the National Electric Code.  My only concern is that the insulation of the SPT is not rated for outdoor use.  But, since these units are not listed, and are to be used only for personal hobby, there is probably no need to comply with these codes.  (I am not being sarcastic)  RJ,  you do a great job, keep it up.

[memphislights]

After looking throught the PC power cords that I had lying around, I realized that all I had were 18AWG cords.  After cutting one open, I have to agree that they are not as suitable as I thought.

Ok, I am thinking about going 14AWG and dual supplying the LE.  I am going by suggestion and the fact that the LOR system uses 2x 14AWG inputs.

I haven't seen much as far as cheap 14AWG power cords.  I was thinking about cutting up a 14AWG extension cord and using the following male plug.

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I figured that I would silicone around the wire and the cap.  I figure that around $1-2 per input cord isn't that bad.

Anyone have any other alternatives?