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Dedicated Lines - specific questions

Very shortly I'll be running five dedicated 20A lines into my den for the audio and vedeo systems. I've read a number of very informitive posts both here on Audiogon and elsewhere, and I'm now convinced that I know just enough to be dangerous! I have several questions, and any assistance that you could provide would be welcomed.

1. I will be using five Hubbell 20 amp hospital grade outlets (modle 8300) that are currently being Cryo frozen thanks to Albert Porter. Before I continue, I would like to thank Albert for his generous offer to us all in arranging a bulk purchase of the outlets & Cryo freezing. This has turned out to be an enormous task, and I feel Albert deserves to be commended for his efforts!
2. The outlets will be housed in a plastic box to prevent them from touching any source of ground, with the exception of a dedicated ground wire to each.
3. The wire I have decided upon is #10 solid copper THHN. The wires will be pulled through exterior metal conduit, and attached to the side of my house. The length of the run is roughly 50 feet, and the conduit will be grounded at the sub-panel. There seems to be some difference of opinion whether solid or stranded is superior, however since I am running three wires (positive, neutral, and ground) for each of the five circuts a distance of roughly 50 feet, the cost of stranded wire would be prohibitive. In several different posts, Bob Bundus explained how he spun the three wires (for each circut) together with a drill, and was very happy with the sonic results. My question is: IS IT STILL BENEFICIAL TO WIND THE WIRES LIKE THIS IF THE WIRES ARE PULLED THROUGH A GROUNDED METAL CONDUIT? I DON'T REMEMBER BOB SAYING IF THE WOUND BUNDLE OF WIRES WAS PULLED THROUGH A CONDUIT OR NOT. IF THE BENIFIT OBTAINED BY WINDING THE WIRES IS ALREADY ACCOMPLISHED WITH THE GROUNDED METAL CONDUIT, IT WOULD THEN SEEM TO ME THAT A GOOD QUALITY ROMEX WOULD BE SUFFICIENT. ALSO, WHAT BRAND OF WIRE DO YOU LIKE, AND WHERE SHOULD IT BE PURCHASED THROUGH?
4. Since my circut breaker panel is completely full, I will need to have a sub-panel installed. I intend on using ceramic fuses instead of breakers providing it will pass the local building code. AGAIN, DO YOU HAVE ANY FAVORITES WHEN IT COMES TO THE MANUFACTURER OF THE BOX AND FUSES, AND WHERE SHOULD I GET THEM FROM? MY EXISTING CIRCUT BREAKER BOX IS MADE BY G.E.
5. Unless I misunderstood from my conversation with Albert (very possible...), it may be best to connect the ground wires to ground as soon as possible, and then from that point, to the main ground bar for the house. I AM THEREFORE PLANNING TO RUN THE FIVE GROUND WIRES FROM THE PLASTIC BOX (THROUGH THE GROUNDED METAL CONDUIT) TO A GROUNDED WATER PIPE ABOUT 25 FEET FROM THE HUBBELLS, AND THEN FROM THAT POINT ON THE WATER PIPE, BACK INTO THE CONDUIT AND ON TO THE MAIN GROUND BAR FOR THE HOUSE. IS THIS CORRECT? DOES IT MAKE SENCE? AFTER CONNECTING TO THE WATER PIPE, SHOULD I CONTINUE RUNNING THE SAME 5 GROUND WIRES, OR CHANGE THEM TO ONE LARGE WIRE SUCH AS A #6, AND IF SO, SHOULD THAT #6 BE RUN BACK INSIDE THE CONDUIT TO THE SUB-PANEL, OR SIMPLY RUN IT OUTSIDE OF THE CONDUIT?

Like I said, I now know enough to be dangerous! Thanks for any help you can provide. Ken Gootkin
kgproperties

Showing 2 responses by bob_bundus

bob_bundus
1,834 posts
 
Hi Ken I used metal conduit in my own installation, not the solid-wall conduit but the flexy Greenfield type. For going outdoors you could get rainwater inside of Greenfield, so SealTight or plain old solid thinwall would be advisable. You get a shielding effect from metal conduit when it is grounded at one end only (grounded at the panel end) but the shielding effect is negated if there's a ground at the load end as well, so a plastic box would avoid that situation.
Ceramic fuses are hard to find, the 20 amp fuses are now plastic body but they seem to sound OK as well, certainly better than glass-body fuses which do sound harsh. I ran out of my old 20 amp ceramics but I did find 30 amp ceramics at the hardware store, so since the #10awg wire is rated for 30 amps that's a safe thing to do. Some have argued that if the outlet is only rated 20 amps then this is risky, but I do not agree it likely that any significant short circuit fault at the outlet is going to draw the line at just under fused rating & therefor start a fire. Sure it's possible, but so is The Bears making the playoffs this season, if you catch my drift.
Gs's advice regarding grounding is certainly valid.
If you want an isolated ground, run your subpanel ground to a separate 8' copper grounding rod, then tieline from there back to your household ground at the main service panel to avoid potential hazards.
bob_bundus
1,834 posts
 
try an industrial electrical supply if you can't find it at the hardware store. I found mine on 50 foot long spools at the farm store - very economical.
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