Poor Man's Busbar--& copper tubing ampacity


First, try finding copper busbar. Second, try affording it.... goodgawd...

Third, ever wonder what the current-carrying capacity of rigid copper tubing is? It's fairly staggering: My calcs yield, ito of number of an equivalent number of #12 solid wire:

1/2 copper, thin wall (red): 10 wires. 1/2 copper, thk (blue): 15 wires 3/4 copper, thin: 22 wires 3/32 x 3/4 busbar: 15 wires

Figger 30+ amps per wire (uninsulated, and proly a conservative number), and wow.... 300 to 660+ amps!

Squeeze/hammer the tubing flat, (soft copper tubing no doubt is easier), and voila, poor man's busbar. I used a vise to start, finished w/ a lump hammer. Wished I had an arbor press!

Proly not tap-able like real busbar, but not really an issue w/ nutted-on lugs--HD carries them. HD also started carrying 3 ph panels--fairly recently, I believe--$95-120, about 24 circuits.. Proly one of HD few worthwhile functions is sockin' it to these rip-off electrical supply houses

Altho busbar is not easily available locally, "neutral bars" are--drilled, tapped, ready to go. BUT, in aluminum. :( Interestingly, these neutral bars look anodized--mebbe they're just tumbled nicely--but anodized alum is a much shitty-er conductor than even aluminum. The initial oxidized layer forms within minutes on freshly cut alumn, so if doing radio/antenna work w/ joined alum components, it can be important to make the mechanical joints quickly. fwiw.

-- Mr. P.V.'d formerly Droll Troll

Reply to
Proctologically Violated©®
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McMaster has it for not too much, I looked at it recently. Say, 3/4" by 1/8" by 6 (or 8) feet long. See item 8964K74 for $20. It is a lot of copper and it is much more conductive than the copper used in pipe.


Reply to

You have stolen my method for making copper gutter pipe hangers.

Reply to
Richard J Kinch

Are you sure it's the same quality stuff? An example is 4' flourescent light bulbs from any place consumers shop tend to really suck.

Reply to
Cydrome Leader

Copper producers were really taking a big beating in the late

90's/early 2000's, prices were as low as 50 cents a pound. Since then the prices have gone up to close to $2/pound and stockpiles are running really low. I've read a couple of reports that in the next 50 years all copper that is economically accessible will have been mined.

But the prices spiked at nearly $2/pound in the 70's and early 80's a couple times. I this was related to instabilities in the commodities market (related to the grossly inflated values for gold and silver) rather than anything real.

Do a Google search for "General Groves", "silver", and "ounces" for the copper substitute and how you can get some if you really really need it :-).


Reply to
Tim Shoppa

At that level, terminating cables becomes really problematic. You enter the world of hydraulic crimpers and Cadwelds. Where I work we do these all the time, but we've got tens of thousands of junctions carrying tens of thousands of amps, and if one of them fails we're on the front page of the newspaper the next day, so we need that.

At PPOE's the preferred method was to use copper tubing and pump chilled water through the center, but that was a different application. Fun building plasma chambers out of kitchen kettles though :-).

You're working at a different point on the price curve, and probably can't afford $3000 hydraulic crimpers and all the pyrotechnics of a cadweld, huh? I'd be interested in hearing more of what a "nutted-on lug" is (drilling a hole and bolting on a lug maybe with some extra clamping plates?) and how it does at carrying 1000 amps for an hour or something.


Reply to
Tim Shoppa

I bought a 1/4 x 2x48 bar on ebay for $22 last fall and have been chopping it up for buss bars on the boat. Use the pot tinning kit I bought to redeem myself for over heating SWMBO's fancy soup pot to tin the bars and made some pretty professional looking busses. It is the pure copper bolts that will eat you a new one. I am using bronze studs for the terminal screws.

Reply to
Glenn Ashmore

And if you buy the "same" product from a wholesaler it sucks just as bad. Contrary to common belief, the supplier does not run 2 different assembly lines, or 2 levels of quality for the same part number, just to sell it cheaper from one distributor than another.

It IS true that retailers often sell substandard product lines - but they are not the same manufacturer/part number/model etc

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Reply to
clare at snyder.on.ca

According to Tim Shoppa :

[ ... ]

The hydraulic crimpers are available if you watch eBay carefully. I've got two sizes of hydraulic crimpers -- one for the range from #8 through #2, and the other for the range from 1/0 through

4/0. I have all of the corresponding die sets except for the 4/0 (so far).

The smaller size is available as a hand-held hydraulic crimper, or as a head which can be connected to a separate pump via a hose. (I've got both of those.) The larger size I have only in the form of the separate head. For driving the separate heads, I have a choice of an Enerpac hand-operated hydraulic pump, or an electric one (from AMP) which cycles up to the maximum pressure and then automatically releases. (I got that in a surplus sale many years ago, and recognized it as being intended to drive the 4/0 crimper head which I once used at work many years ago -- so I held onto it hoping to get the head and the dies. Well -- I've got it all except for the 4/0 dies now. :-) (These all are for the PIDG insulated terminals, not for the bare metal ones.)

I *think* that I have seen what he is talking about. Start with a lug which has as the extension where the wire attaches a vertical threaded post which has a slot milled through it through most of its height. The bottom of the slot is rigged to grip the wires. Into this is dropped a presser bar with similar ridges. It has a projection which passes through a nut which threads onto the post, and a couple of ears of the projetion are bent over so when you loosen the nut, it lifts the presser bar. They appear to be made of either copper or a bronze which looks similar to copper.

I've seen the assembly without the tab as well, used for splicing heavy gauge wires, and expected to be wrapped with lots of insulating tape. :-)

Enjoy, DoN.

Reply to
DoN. Nichols

Where the rip-off comes in at supply houses is the "free credit accounts" - As a wise man once said: TANSTAAFL. And the ones who factor their inventory and accounts receivable to an outside financial institution are worse - more hands sticking out for their cut.

Same reason the prices on the roving tool supply trucks are so high, they figure in the 'Free Financing' for the mechanics.

It's the same stuff at HD - as in your lamp example, some wholesale houses carry the 'crap' quality level lamps (and wiring devices, boxes, can lights and trims, etc.) to get their prices down, as well as the better stuff for customers who know and specify it.

Buying the crap usually doesn't pay, because you'll be eating the call-backs that can easily cost far more than the money you saved.

HD can charge less than the average regional supply house because they're buying light bulbs by the train-load for a national chain (not a few pallets at a time) and that gets you a serious volume discount. The only place this falls apart is the packaging is different for retail and costs a bit more. (So you get the 'Contractor Pack'.)

The 3-phase items they carry are Murray (Siemens) and for plug-in breakers they're a good solid quality. But they only keep a few sizes of 3Ph 208/240V panels and breakers in stock, good for those weekend emergencies where you need to get it fixed NOW!

(The supply house will be glad to come open up for you on the weekend for that emergency part you need - for a 'nominal' $75 or $100 fee. After you track someone down, and wait for them to drive in.)

For most 3-Ph work you still have to go to a wholesaler who has a broader line, to get that 3-pole 70A. Or to get Bolt-on panels and breakers or 480V breakers.

But when I don't feel like dealing with the attitude, or I need the

2X4's and drywall to patch the wall after I swap the panel, I go to HD and get it all in one stop.


Reply to
Bruce L. Bergman

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