Outlet Question

@zlone : Mechanical and electrical.

Mechanically it’s what keeps the assembly firmly attached to the box no matter how much force you use to insert a plug.

Electrically It is  what the ground conductor screw attaches to.  The same strap then goes to the ground pins in the socket as well as the top and bottom tabs which ensure the box they are in is also grounded, if metal. 

Note the difference between residential and commercial. In residential the strap is internal and towards the front, while in commercial it is wrapped around the back.

OP:

A peculiarity of the code is that 15A and 20A outlets may be used on 20A circuits. For this, the two types have identical quality and current capacities. Meaning there’s no point in putting in a 20A outlet in a 15A circuit, it’s not built better. Some makers even use EXACTLY the same conductors in both models, but different face plates to save money.

The theory here is that some circuits, like the kitchen counter, may need a 20A circuit to handle multiple appliances at the same time without nuisance tripping.  So the circuit is 20A, but each outlet may have a 15A face plate. The outlets still have to be safe to use on the 20A circuit, so the construction is always the same. 15A outlets do not have thinner conductors.

However, no, you should not put a 20A plug on a 15A outlet as the T shaped hot pin indicates it is safe to use for 20A devices, like industrial vacuum cleaners.

*ensure

Hi OP!

So, lets get regulations out of the way first. Outlets in a home today must be tamper resistant. I don’t know of any "audio" grade outlet ( and I use the term sneeringly) which has this feature. Of course if you are retrofitting 1 outlet in an older home without kids you may not care.

The minimum I install anywhere in my house is the combined commercial/residential. Meaning they are ruggedized for commercial use but include the TR features for home. Lowe’s has 10 packs of Eaton’s for about $45.

As for hospital grade, Eaton, Hubbell and Leviton are good sources. Again, you should use hospital grade + tamper resistant to be fully code compliant.

Also see the discussion here for accessories to insure a solid outlet.

I also use 90 degree hospital grade plugs which give me back floor space and if you turn them the right way you can put 2 in an outlet. The combination of the HG plug and socket is very tight.