Carhartts, Blåkläder - probably other brands that still actually sell work clothes - tend to have separate "fashion" models that sell through typical fashion stores. They're generally higher price and less durable in my experience.

In the US it's not hard to find regular carhartts work wear - in Norway I've only seen the fashion stuff. On the other hand, Blåkläder operate a few outlets that are aimed at the business market - and there it's possible to buy their "actual" work clothes.

Ed: in addition to such work wear, military surplus & second hand is also a good bet.