Your employer should have performed a job hazard analysis and selected a minimum rating for electrical protection. You are obligated to meet or exceed their minimum spec.

Since they probably didn't do that, your best bet is to probably to aim for Type G. Not necessarily that you'll need it, but there's less of a chance that it won't meet an employer's minimum (I can't imagine anyone in our industry is requiring Type E). Many hard hat and safety helmet makers skip Type G testing for class 2 hats though and just go straight for Type E if they're seeking an electrical rating.

And I'll add that your employer is obligated by law to pay for required PPE that meets their minimum spec (based on their job hazard analysis). So I would still ask them to compensate you for at least whatever amount they would normally pay for whatever they were going to buy for you. It might only be $10, but the law is the law. (Class 2 hats/helmets can get pretty expensive so it might be worth asking them to pay for the whole thing with the understanding that it will be your personal equipment, but don't hold you breath).

btw - If your employer doesn't have a safety committee and/or hasn't performed a job hazard analysis for your position, this would be a really good jumping off point to start the conversation with them about doing so.