Copper Bars, Flats, Sheets, Wire and Tubes from S.P. Road

Electrolytic tough pitch copper (Cu-ETP, UNS C11000) carries at least 99.90 % copper, silver counted as copper, and is made to conduct at 100 % IACS when annealed. It is the default for busbars, earthing conductors, switchgear parts and bare conductor wire. Our page on E.C. grade copper covers the chemistry and the standards behind it.

Commercial quality copper is ordinary copper for mechanical and decorative work, where nobody is going to put a conductivity meter on it: gaskets, spun vessels, ornamental sheet, general fabrication. If the end use is electrical, buy E.C. grade and ask for the conductivity figure on the certificate. The price gap is small next to the cost of a panel that runs hot.

The same copper behaves very differently depending on how it was last processed. Cold work makes it stiff and strong; annealing makes it soft enough to bend round a tight radius. A plating on top changes how it handles corrosion, solder and heat.

• Hard drawn copper: cold drawn with no anneal afterwards, for conductors that must hold their shape or carry load
• Soft annealed copper: heat treated after drawing, for windings, flexible links and anything formed on site
• Tinned copper: tin coated for solderability and protection in damp or sulphur-laden air
• Nickel plated copper: nickel coated for higher service temperatures and a harder surface

Our product sheet lists copper round bars, square and hexagonal bars, flats, strips, sheets, plates, circles and wires, plus pipes and tubes in straight and coil form, both Indian-made and imported. Each form has its own page with sizes, weights and ordering notes, linked below. Each tends to go to a different kind of buyer: busbar flats to panel shops, ACR coils to HVAC contractors, circles to vessel makers and spinners, earthing strip and plate to electrical contractors.

ETP copper keeps a small amount of oxygen, around 0.04 %, locked up as copper oxide. That oxygen does no harm to conductivity, but if ETP is heated in a hydrogen-bearing atmosphere, as happens during torch brazing, the hydrogen reacts with the oxide, forms steam inside the metal and can crack it along the grain boundaries.

DHP copper is deoxidised with phosphorus, so there is no oxide for hydrogen to attack. It brazes and welds well, which is why water, gas and refrigeration tubes are DHP. The price you pay is conductivity: the residual phosphorus pulls it down to roughly 85 % IACS. Rule of thumb: ETP for anything that carries current, DHP for anything that carries fluid.

A quote turns round faster when the enquiry says grade (E.C. or commercial), form and size, temper, any plating, quantity in kilograms or pieces, and which standard the certificate should refer to. If you only know the application, tell us that. A note like 'busbar for a 630 A LT panel, tinned' or 'ACR coil for split AC installs' is enough to start.