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Copper Specifications

Feb 092010

The variables facing the designer of a copper fabrication are many. The impact these variables will have on the finished copper component range from significant to minimal. The purpose of the following information is to provide an awareness for the designer as to the importance of these copper specifications. However, in many cases the number of options described here are limited dramatically in application because of material availability, manufacturability, minimum raw material orders and cost. Therefore, STORM will be happy to review your specification and provide comments as to cost and availability.

Copper Busbar Efficiency

Busbar systems for industrial and commercial facilities are often designed to minimize first costs, with the Busbar sized to the minimum permitted by safety considerations. In such cases, operating costs are ignored at the design stage and, as a result, large amounts of electrical energy are wasted in service due to heating. Larger cross-sections of Busbar result in more efficient systems with lower operating costs. The optimum system is one that properly balances first costs with operating costs in order to minimize total life-cycle cost.

Energy is wasted in any system because a portion of the electricity flowing through the conductor is converted to heat rather than being delivered as usable electrical energy. The determinants of the rate at which heat is generated by a system are: the amperage of the system and several factors which determine the resistance: the dimensions of the Busbar, the layout of the Busbar and the conductivity of the Busbar metal.

The effect of electrical conductivity on the heat loss of the system is straightforward: there is a proportionally inverse relationship between the two. The effects of the amperage and the dimensions of the Busbar are more subtle and have to be considered together. For a given Busbar size, increasing the amperage of the system will increase the heat loss, while increasing the cross-section of the Busbar will decrease the electrical resistance, and therefore the heat loss. These two effects are nonlinear, however. Thin, wide Busbar systems have better heat-dissipation characteristics, and therefore run cooler, than Busbar systems of equal cross-sectional area, but with less surface area. Since electrical resistivity rises with temperature, the thinner, wider configurations are better conductors.

Copper Alloys

C11000, Electrolytic Tough Pitch Copper (ETP): The most common type of copper used. With a minimum copper content of 99.90%, and an electrical conductivity of 101% IACS, it is used in such diverse applications as electrical conductors, roofing and flashing, heat exchanger fins, tanks and hollowware.

C10100 and C10200, Oxygen Free Coppers: Used where the presence of oxygen in copper is undesirable, as in certain electronic parts, or metal to be welded. These coppers have higher purities than ETP and are cast by the refineries in a controlled atmosphere with oxygen excluded. Cryogenic grades of C10100 copper are also available.

C12200, Phosphorous Deoxidized Copper (DHP): Deoxidized with phosphorous, making it relatively easy to weld and high temperature braze. However, DHP has a much lower electrical conductivity – approximately 85% IACS.

C11400 and C14300 Coppers: Used where it is desired to avoid softening in copper that is soldered at relatively high temperatures, as in automotive heater and radiator fins. The addition of a small percentage of silver, as in C11400 copper, is effective without a significant change in thermal and electrical conductivities. The addition of .07% cadmium to C14300 copper has a similar result, except that the conductivities are reduced by approximately 4%.

The measure by which the electrical conductivity of all materials are compared is known as % IACS (percent International Annealed Copper Standard). A few comparative conductivity ratings follow:

Type of Metal % IACS
110 Electrolytic Tough-Pitch Copper…………………………………………………………….	101
102 Oxygen-Free Copper…………………………………………………………………………..	101
145 Tellurium Copper………………………………………………………………………………..	95
Aluminum EC…………………………………………………………………………………………..	62
Aluminum 6101………………………………………………………………………………………..	56
505 Phosphor Bronze 1.25%………………………………………………………………………..	48
Aluminum 5052………………………………………………………………………………………..	35
Stainless Steel 302…………………………………………………………………………………….	3

Based on the availability and cost, C11000 Electrolytic Tough Pitch (ETP) should be specified when suitable.

Temper

The hardness of the copper or copper alloys are obtained by annealing or cold finishing after the annealing process. Unlike steel and aluminum, copper and copper alloys are not strengthened by heat treating in the final stages of processing. During annealing, air is excluded by flooding the furnaces with protective atmospheres controlled to prevent scaling, staining, or the penetration of the metal by oxygen or hydrogen. Cold finishing is defined as the permanent deformation or strain produced in the metal by external forces that are applied while the metal’s temperature is below its recrystallization point. It can be achieved by rolling, bending, stretching, or hammering the metal while it is cold.

Copper Rod and Bar

Annealed Metal (Soft) – Recrystalized Grains – Produced by Annealing Hard Metal – Special Soft Tempers are used for short radius bending, cold heading and cold swaging. Cold worked surfaces are suitable for most polishing.

1/2 Hard Metal (Cold Worked) – Distorted and Broken-up Grains – Produced by Cold Drawing or Cold Rolling Soft Metal to Finish Size. Common Hard Temper Rectangular and Square Bar. Standard Bus Bar Temper. Used for parts requiring machining, large radius bends, slight cold heading and slight cold swaging.

Full Hard Temper (Cold Worked) – Much Distorted and Broken-up Grains – Produced by Cold Drawing or Cold Rolling Soft Metal to Finish Size. Common Hard Temper for Round Rods. Used for parts requiring machining. Generally not suitable for bending, cold heading and cold swaging. Hard tempers are favorable to blanking, shearing and machining.

Sheet, Strip and Roll Copper

Cold Rolled Annealed Temper (Soft Metal) – Recrystalized Grains – Produced by Annealing Hard Metal – Standard Soft Roll Copper is commonly used for deep drawing and spinning. The surface on drawn parts is suitable for most polishing requirements.

Soft Temper Annealed Metal (Soft Metal) – Recrystalized Grains – Produced by Annealing Hard Metal – Commonly used by sheet metal craftsmen. Used for moderate drawing and cupping. The surface on drawn parts is suitable for most polishing requirements.

1/4 Hard Metal (Cold Worked) - Distorted and Broken-up Grains – Produced by Cold Rolling Soft Metal to the Finish Thickness. Special Hard Temper suitable for shallow forming.

1/2 Hard Metal (Cold Worked) - Distorted and Broken-up Grains – Produced by Cold Rolling Soft Metal to the Finish Thickness. Special Hard Temper suitable for 90 deg. bends.

3/4 Hard Metal (Cold Worked) – Much Distorted and Broken-up grains – Produced by cold Rolling Soft Metal to the Finish Thickness. Suitable for 90 deg. bends. Favorable to blanking, shearing and machining.

Because of the relationship between Temper and the manufacturability of the component, Storm Copper Components will suggest a Temper upon review of drawings.

A Guide to Copper Bus and Electrical Ground Bars

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Feb 032010

Electrical engineers and designers face a set of variables that often have a significant impact on a finished copper component. The following information illustrates this design process by listing the importance of key specifications related to producing efficient copper bus and electrical ground bars.

In many cases, the options described may be limited in application because of copper alloy or other metal considerations, manufacturing capabilities, or simply the high cost of copper in today’s market.

Copper Bus Bar Efficiency: Make no mistake, size really matters

Bus bar systems for industrial and commercial facilities are often designed to save costs, with the bus bars sized to the minimum safety requirements permitted by local electrical codes. Often the future operating costs are ignored during the design stage, which can result in large amounts of wasted electrical energy due to the inefficient bus-bar conductivity or heating.

While opting for larger cross-sections of bus bar can result in more efficient power distribution grounding systems – with less heating and lower operating costs – the optimum system is one that properly balances initial costs with operating costs in order to minimize total life-cycle cost.

Energy is most often wasted in power or grounding systems because a portion of the electricity flowing through the conductor (bus or ground bar) is converted to heat rather than being delivered as usable electrical energy. The factors that determine the rate at which heat is generated by a bus bar system include:

• The amperage of the system with several factors that determine the resistance.

• The design of bus bar, the cross-section dimensions and the system layout.

• The conductivity of the bus bar metal, e.g. Copper vs. Aluminum.

While inefficient electrical conductivity leads to heat loss, there is a proportionally inverse relationship between the two that can be solved by increasing the bus bar dimensions. Yet the effects of the amperage and the bus bar dimensions are harder to discern.

Once the bus bar dimensions are set and a system is laid out, any increase in amperage down the line will increase the heat loss. Designing a larger cross-section of bus bar will naturally decrease electrical resistance and heat loss. But when is enough, enough?

Interestingly, the effects of amperage vs. dimensions are nonlinear. Thinner, wider bus bar systems actually have better heat-dissipation characteristics and run cooler than heavier bus bars that have less surface area. Since electrical resistance rises with temperature, the thinner, wider configurations are better conductors. Go figure.

Here’s an illustration:

Click here to view a set of key ampacity tables.

For customers who lack an engineering degree or Einstein’s brain, please be aware that in addition to this design guide, Storm Copper Quality Team members are on hand to review your specification and provide assistance in discerning ways to reduce cost and lead times.

You can reach them by calling Storm’s OEM Hotline: 1-800-394-4804

Here’s what Storm’s co-owner, Dan Kitts, writes about copper bus bar fabrication…

Whenever Storm’s process engineers look at a bus bar print, there are a handful of key design elements they are immediately drawn to. These design elements largely dictate how an OEM’s bus bars will be manufactured. And it also determines the price we must charge to the customer.

When considering the design of a bus bar, several critical points can favorably impact the cost of fabrication. Each falls within a quality process that Storm calls “Value Engineering…”

Read the rest of Dan’s Value Engineering Blog …

Copper Bus Bar Fabrication and Plating – Important Considerations

Storm manufacturers copper bus and electrical ground bars and kits for installations including perimeter grounding, telecommunications centers, towers and antennas. In each of these installations, one of the key factors in producing a cost effective busbar begins with layout of the required holes. From a fabrication standpoint, on copper busbar less than .500” thick, punching holes is much more cost effective than milling holes. The holes in a busbar are always punched in while the stock is flat, and then any required bends are made. When holes are specified too close to a bend, the holes can become distorted slightly. Even a slight distortion can prevent the installation of other components when tolerances are tight, so the only solution is milling holes that are designed too close to a bend. Milling is a slow and expensive process that is easily avoidable by allowing a distance of 1.00” or more from a hole location to a bend in the part.

Another reason that drives up costs, through required milling is tolerance. When hole placement tolerance is less than +/- .005” it is impossible to hold these dimensions on our punch presses. Also, the tolerance of the hole diameter is a concern. When specifications call for +/- .001, we must use a mill to drill the hole. To avoid incurring the additional costs of milling, keep your tolerances to +/- .020”.

It is important to note that punching copper busbar does slightly deform the surface of the part. Occasionally this indenting or rounding of the surface of the busbar can result in a loss of contact area. This minor deformation of the hole is rarely a problem, but worth noting.

Storm’s prototyping capability can also put samples of bus bar connectors in your hands for evaluation in a matter of days. And because Storm offers in-house bus bar electroplating of tin, lead, tin/lead alloys and silver, lead times critical OEM delivery requirements are reduced. Plus internal plating is more cost effective than outsourcing.

Un-plated vs. Tin-plated?

Pure Copper Grounding Bars are the industry standard because of the excellent conductivity of copper. But Storm also offers in-house electroplating of fabricated bus bar. This allows quick response to critical OEM delivery requirements. Moreover, internal plating is more cost effective than outsourcing.

Tin-Plated Grounding Bars can be a better choice for outdoor or other harsh environments, as tin electro-plating reduces the chance of corrosion interfering with the ground connection. Tin plating also disguises the copper color, serving as a secondary theft deterrent, while making the copper unusable for illegal recycling.

Security Ground Bar Kits are also available to prevent theft of copper by replacing the standard hex bolt configuration with Truss Spanner Security Bolts.

For more information on protecting against copper theft, check out our Copper Crime Center

Storm also offers custom stamping for theft prevention. Allow us to stamp your company name, logo, phone number, or a Do Not Recycle message into each ground bar. For more information, link to our live chat center or call toll free: 1-888-334-2177.

Ground Bar Kits were developed by Storm to save time and money, and include the following components:

One .25″ thick grounding bar of solid copper (110 Electrolytic Tough-Pitch).
Standoff Insulators: A
Mounting Brackets: B
Stainless Hex Bolts: C
Stainless Spring-Lock Washers: D

Storm also offers Clear Polycarbonate Ground Bar Cover Kits to protect workers and equipment from accidental contact with live voltage.

Busbar Fabrication – Cost effective design

Copper Buying Guide, Customer Buying Tips Comments Off

Jan 202010

By Dan Kitts

On average, 17,000 copper connectors, aka busbars, ship from Storm Copper’s loading dock every day. Thousands of unique designs are included in those 17,000 pieces of copper busbar. Needless to say, we have seen countless prints from many different industries. When our process engineers look at a print, there are a handful of key design elements they are immediately drawn to. These design elements largely dictate how these busbars will be manufactured. It also determines the price we must charge our customer. When considering the design of a busbar, several critical points can favorably impact the cost of fabrication.

Although it may sound obvious, the number one factor in keeping busbar pricing low is often overlooked. Specify only the exact size of copper stock you really need for the job. Whether you are using copper or aluminum for your busbar application, reducing the metal content is your number one opportunity to reduce cost. You will find these ampacity tables very helpful with sizing busbar. To do this properly, you must know the amount of temperature rise you are willing to accept.

One word of caution while we are on this subject; your desire for thickness optimization should not conclude in a special mill run sizes of busbar. Unless you are a very large user of busbar, utilizing readily available busbar thicknesses (these are .062, .094, .125, .250, .312, .375 and .500 inches) permits your fabricator multiple sources of supply and reduced lead times. As of the writing of this article, lead times from the two domestic copper mills in the United States are approximately 8 weeks. Most OEMs we do business with require a lead time of 2 weeks or less on their busbar requirements.

From a fabrication standpoint, punching holes in copper busbar is much more cost effective than milling holes. On busbar less than .500” thick, there generally are two design parameters which force busbar to be routed to the mill. The first is a hole location so close to a formed or bent area of the busbar that the hole becomes deformed. You see, busbar is always punched when it is flat. The only way we can get a hole into a bent busbar is by mounting it on the mill or machining center. This process is slow and therefore expensive. If you can allow a distance of 1.00” or more from a hole location to a bend in the part, we can most often eliminate a stop at the mill.

The next reason a busbar often stops at the mill is tolerance. Once your tolerance gets under +/- .005” on hole placement, we can no long hold these dimensions on our punch presses. Also, the tolerance of the hole diameter is a concern, +/- .001” and we must use a mill to drill the hole. To be sure your part stays off the mill, allow +/- .020” for your tolerance. It is important to note that punching copper busbar does slightly deform the surface of the part.

Occasionally this indenting or rounding of the surface of the busbar can result in a loss of contact area. This minor deformation of the hole is rarely a problem, but worth noting.

To sum up the critical points in reducing busbar cost:

1. Use the smallest possible size to reduce metal content of the busbar.
2. Design in standard thickness busbar to improve availability whenever possible.
3. Review hole placement and tolerance to reduce the chance the busbar would need to be routed to the mill.

Our Busbar Capability Brochure is another source of information that may be of assistance in your design efforts.

If you already have a print of your custom Busbar, simply email it to busbar@stormcopper.com for a fast, reliable quote. If not, good luck on your busbar design efforts, and please feel free to contact us if you have any questions. Our OEM HOTLINE is 1-800-394-4804.

Custom Fabrication, a Storm Copper Specialty

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Dec 142009

Storm's highly skilled technicians and craftsmen create custom orders to exacting specifications.

Storm Copper Components is one of the largest fabricators of copper busbars, laminated busbars and copper ground busbars in the United States. Literally tons of finished copper products for all types of electrical applications are in their warehouse, but Storm also has the equipment and highly skilled technicians to custom fabricate copper based on a customer’s individual needs, large or small.

Storm’s custom fabricating capabilities fall into several categories, listed below. And sometimes a job may require several of these processes for the same piece. When the process goes from simple to complex, that’s were Storm’s exceptional tooling skills and specialty equipment give them a leg up.

With the advantage of Flex-Tooling equipment, Storm can produce specialty items that would normally require lengthy and expensive Hard Die tooling, in a fraction of the time and cost as some competitive copper suppliers. And, unless there is a very unusual template involved, customers will never be charged a Hard Die setup charge, because they don’t need them.

Storm’s materials, processes, and finished components are engineered to meet, as needed, standards required by ASME, UL, CSA, Bellcore, and other testing/standards bodies. Since virtually every part they make is custom to a particular manufacturer or application, Storm has created a number of new cost effective techniques of producing connectors in both low and high volume production runs.

Punching - This type of copper fabricating is done CNC punches. These punches have multiple tool holders and have the tonnage to punch up to .500″ thick copper bar and plate. The tolerance with this particular copper fabricating equipment is +/- .020″.

Stamping – This method of copper fabricating is performed with high tonnage presses. Even so, the maximum thickness copper typically stamped is .250″. The tolerance on this method of copper fabricating varies depending on the tooling employed.

Turret Punching - This piece of equipment performs punching and cutting the outside perimeter of the copper part. This is the primary method of producing parts with odd shapes, tabs or fingers. Generally, the thickness of the copper is .250″ and less. Tolerances associated with this particular process is +/- .005″.

Machining – This method of fabricating copper, also known as milling, has the greatest versatility and can produce an almost endless array of copper fabrications. Moreover, tolerances as close as .001″ can be achieved with this equipment. Unfortunately, it is also a relatively higher cost method of production because of the significant set-up and tooling costs.

Forming - This is a secondary step in the copper fabricating process and is performed after the part has been cut to length and punched or milled. During this process the part is bent or formed to the specifications of the print.

Plating - This is normally the final step in the copper fabricating process. Storm can electroplate tin, lead, numerous tin/lead alloys, silver and nickel. It is worth noting that the copper parts are deburred prior the electroplating operation.

So, no matter how much punching, stamping, machining, forming or plating your project requires, Storm can do the job better, faster, and more economically.

For a fast, no obligation quote, call 1-800-394-4804.

A tip on thickness and flexibility

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Nov 202009

When shopping for copper or stainless steel sheeting, and flexibility is an issue, here’s a tip to help you understand and compare the thickness and flexibility of these metals. The thickness of metal sheeting is listed in decimals. Metal sheeting with the thickness of .010, compared to our American system of fractions, would measure to less than 1/64 inch.

Now, let’s go one step further and give you a comparison of the flexibility of the metal that you can relate to an item in your everyday life. If you may have a Blockbuster membership card or a Bonus rewards card, copper sheeting with a .010 thickness will have the same flexibility as either of these cards.

Keep in mind that these two cards are thinner than a standard credit card which is less flexible. A standard credit card measures .028. This compares closely to .0216 copper foil, but the foil is slightly stiffer. Some other measurements that are convenient comparisons to everyday items are listed below.

Penny .05
Dime .062
Nickle .07
Quarter .067
Half dollar .085

Copper Buying Guide

Copper Buying Guide, Copper Grounding Bars, Customer Buying Tips Comments Off

Nov 202009

By Dan Kitts

Coil Sheeting is very flexible and is used in countless ways including flashing, crafts and decorative applications

Selecting the right type of copper for any application requires an understanding of some rather technical terms like: alloy, temper, hardness, gauge and finish. Don’t be put off by the number of terms. When taken one at a time they’re not that difficult to understand. So please, stick with me through this brief article and you will have a greater understanding of copper and have the confidence to purchase for any application.

Alloy

Copper Sheet, foil, bar, rod and tube is available in many different alloys. These different alloys give certain physical properties to copper it doesn’t usually have, but those new properties often bring new limitations as well. What makes the alloy discussion a little easier is that 99% of the copper sold in the United States is represented by the three alloys listed below.

C11000
Most of the copper sold today in the United States is alloy C11000, also known as Electrolytic-Tough-Pitch. Plain and simply, C11000 is 99.9% pure copper. It makes an excellent electrical conductor, an equipment ground bar, a fine looking kick plate on your front door, does a great job as a back splash in your kitchen, makes a very classy looking rain gutter and adorns some of the finest looking roofs in the world.

Because Storm Grounding maintains a million-pounds of copper inventory, barstock orders usually ship the next business day. Copper Barstock is also available custom cut to specific lengths.

C12200
Copper used for tube and pipe is usually alloy C12200. You get this alloy by adding a very small amount of phosphorus to pure copper. This makes the copper easier to weld and braze. Unfortunately, it also makes the copper considerably less conductive. Generally speaking, you rarely see this alloy being used for electrical applications, but if you need to weld or braze, this alloy is your best option.

C14500
If you’re going to turn or machine copper, C14500 is your alloy. When copper is alloyed with a small amount of tellurium it greatly improves the ability of copper to “make chips”. Pure copper (alloy C11000) tends to be “gummy” (I apologize for using such a technical term) when machining. This gumminess means you have to slow the machining process down quite a bit. Pure copper is also hard on machine tools, which adds to the expense of machining. C14500 is not quite as conductive as pure copper, but it is relatively close.

An interesting fact about copper alloys; if you add a little zinc to the metal – you get brass.

Temper

Basically, the Temper of a metal refers to its hardness. The two extremes of Temper are denoted as “hard” and “soft”. While the Copper Development Association has installed a numbering convention H01(soft) to H04(hard), most people in the industry simply refer to the degree of hardness. “Hey, I’ll take some ‘quarter-hard’ copper sheet,” is really all you have to say to your local copper mill* to call out the Temper.

So, why does anybody even worry about Temper? To a large degree, the hardness of the metal determines the application. If you were to make a beautiful pot rack out of soft Temper copper bars and chose to hang your grandmother’s favorite cast iron frying pan on your new creation, the weight of the frying pan could well deform the rack. Bottom line, if your copper project involves supporting any kind of weight, stick to harder Tempers.

On the other hand, if you are interested in making a copper etching or simply forming the copper by hand, you would be much better off with a softer Temper. Softer Tempers are also easier to cut as well. For decorative and craft applications that do not require supporting much weight, soft Temper should be your choice.

One final point about Temper, because of the end use of the product, copper bar is generally available only in the harder Tempers and copper sheet in softer Tempers. This has to do with how the two different forms of the metal are most commonly used.

Gauge, Oz. and Inches

copper_chart Calling out the gauge of the metal is another way of saying the thickness. It is important to keep in mind that with gauge, the larger the number the thinner the material. 30 gauge copper sheet is much thinner than 16 gauge. To make matters even more confusing, the roofing industry measures copper thickness in ounces per square foot! 16 oz copper sheet is a very common size of roofing copper. Use this cross reference table to help you convert gauge to inches to ounces.

Finish

If you have ever walked in the lower level of a fancy department store and happened to see the gorgeous copper pots hanging in the kitchen department, you have seen an unnatural copper finish. Unless copper is treated with a synthetic lacquer, it will not have that deep mirror-like finish. Also, if that lacquer finish should ever crack (even a very small one) and air reaches the copper, it will discolor fairly rapidly.

Generally, the finish of copper bar and sheet will provide a dull reflection. Occasionally, the metal will also have a slight waviness to it, although it will be very smooth. Over time the metal will darken with exposure to air. The oxygen in the air is actually corroding the metal. Over a number of years a greenish patina will form on the metal. Most people find the character gained by copper through this corrosion process to be quite attractive. As a matter of fact, you can actually purchase copper that has been treated with chemicals which greatly accelerates the corrosion process. If you want that greenish finish on that copper bay window roof right away, not a problem, chemical engineering has provided the product for you. If you would prefer more of a grayish patina, that’s available as well.

Congratulations, you now know the important factors in specifying copper sheet, foil, bar, rod and tubing. Good luck with your project!

*I am being sarcastic about your local copper mill. There are only two full line copper mills in the US. If you want to go direct to the source, bring your check book. The minimum order is at least 5,000 lbs.

Storm Currents News-Blog

Copper Specifications

A Guide to Copper Bus and Electrical Ground Bars

Busbar Fabrication – Cost effective design

Custom Fabrication, a Storm Copper Specialty

A tip on thickness and flexibility

Copper Buying Guide

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