Excavator Noise Level

This has to be measured. They are all different. Your question makes no sense.

If you have to ask, use double ear protection, whatever that is.

Where, on the planet are you?

It also has to be measured in the situation. An excavator doing strip mining work may not require ear protection but the same excavator underground in a coal mine will certainly be much louder. But you're absolutely correct that any and all desired personal protective equipment should be available to a worker.

I did active noise cancellation for 6 years. Headsets, mufflers, appliances, even semi cabs and aircraft. We had a twin Beech in our shop for a year. The tests are very specific, and as you say environment specific.

I didn't go into details because I don't think the OP is equipped for sound analysis.

OP, use all the protection you have.

It sure won't hurt to overdo it. Just like I have to have my reading glasses within reach. Anything I do that might be loud, I throw my hearing protection on.

The reason is, that I didn't always do it that way, and I can tell.

Find out how many decibels the noise is, and compare with how many decibels are allowed at your ears. If the difference is around 20-30 or so, single ear protection may suffice. For greater differences, you may need double. Most earplugs and headsets "top out" at about 32dB of noise reduction; for more than that you need two stages.

I have worked in loud engine rooms over the years, and have been consistent in using ear protection. I haven't tried lately, but as of about 3 years ago, when lying on the sofa, I could still hear my cats walking on the carpet (if the room was otherwise silent).

You've given good advice here.

It doesn't matter what the noise level is at the source, it matters how much acoustic energy gets to the inner ear.

A quiet environment is about 55dB. Anything over that, especially low frequency noise, for long periods is not good.

I can't even hear my dog walk across the room any more. But, he's so old he can't hear me yell at him anyway.

UK noise regulations can be discovered with an internet search. They apply to all workplaces, whether excavators or not.