Can you clip a dog with human hair clippers?

The short answer is no, you should not use human clippers on dogs. You can however safely use dog clippers on humans. There are a few reasons why... 

The blades are different

Blades for dog clipping have different teeth spacing, different teeth lengths, and are sharper compared to the finer, shorter blades used for human hair. That fine teeth spacing of a human blade is why human hair clippers usually grab, 'chew' or pull a dog's coat, instead of cutting it (as if the blade is blunt, even when it's sharp). For puppies in particular, using human hair clippers can cause a negative first experience by pulling the coat and hurting them, which can impact how they feel about being clipped for the rest of their life.

Human hair is different

Human hair is much finer and lighter. We grow one hair from each pore. Humans have one type of hair, called terminal hair. Dogs have 3 to 7 hairs growing from each pore, and although a few dog breeds have hair similar to a human (such as the fine drop-coat of the Yorkie), the majority have a mix of textures.

For many breeds the textures are mixed in the same area of the body, such as a cotton soft undercoat and harsher more wiry top coat. For others the texture changes in different areas of the body. Some dogs have double or triple coats, and all dog coats in general are much thicker and denser compared to our hair.

All of that combines to being more than what human blades and clippers are made to cope with.  

Heat is a concern

Human hair clippers only need to run for short periods of time and only need to clip one, small area of the body (our head). With shorter running times and less hair to cut, blade heat and clipper heat are of minimal concern.

Dog clippers run for a lot longer at a time, and have to clip the entire body, as well as clipping through much denser, thicker hair, so are manufactured differently to reduce overheating.

Keeping the clipper housing from overheating in your hand, and reducing blade heat to avoid burning the dog, are a feature of dog clippers that human clippers do not have. This is also why human clippers can get so hot when you try to use them to clip a dog.