What is actually in there
By weight a liquid filled distribution transformer is mostly core steel and oil. The core is grain oriented electrical steel and is typically the single heaviest component. The windings are copper or aluminium, and on most modern distribution transformers they are aluminium, because aluminium is cheaper and the design compensates with a larger conductor. A 300 kVA unit weighing about 3,500 lb might carry a few hundred pounds of winding metal, not half its weight.
Copper or aluminium, and how to tell
The nameplate states the winding material. If it does not, weight is a clue, since a copper wound unit of the same rating is heavier. Copper wound units command a materially higher scrap price, which is why the question comes up at all. Older units are more likely to be copper, newer distribution units more likely aluminium.
Why you cannot just weigh it
Scrap value depends on separating the fractions. Core steel, winding metal, tank steel, bushings and oil all price differently, and the oil has to be drained and handled rather than simply poured out. A scrap yard quoting a whole unit is pricing the work of separation as much as the metal, which is why a whole transformer fetches far less per pound than clean winding metal does.
The PCB problem on older units
Anything built before the late 1970s may contain askarel fluid with PCBs, and that changes the economics completely. The unit has to be tested, and if contaminated it becomes regulated waste with a disposal cost rather than a scrap value. Provenance matters, which is a reason to be careful buying used equipment of unknown age.
Common questions
How many pounds of copper are in a transformer
It depends on rating and on whether the windings are copper at all, since most modern distribution transformers use aluminium. On a copper wound unit the winding metal is a minority of total weight, with core steel and oil making up most of it. The nameplate states the winding material.
What is a scrap transformer worth
It depends on separating the fractions. Core steel, winding metal, tank steel and oil price separately, and the oil must be drained and handled rather than discarded. A whole unit fetches far less per pound than clean winding metal because the buyer is pricing the separation work.
Are transformer windings copper or aluminium
Most modern distribution transformers use aluminium, which is cheaper and compensated for with a larger conductor. Copper is still specified and is more common on older units. The nameplate states which.
Can old transformers be scrapped safely
Units built before the late 1970s may contain PCBs in the insulating fluid and must be tested first. A contaminated unit is regulated waste with a disposal cost rather than a scrap value.
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