I'm guessing you may be from the other side of the pond?
I would start by looking at it from your side of the world and see what standards you would apply locally. If you've built something similar in your country, ask the Notified body if they know what the equivalent US standards might be.
Assuming you're armed with the equivalent US Standards, read and understand them in your applications, you now need to find an NRTL (
National Recognized Testing Laboratory, the equivalent to a EU Notified body). In the US, NRTL's are approved by OSHA. NRTL's also have to be accredited by OSHA to use a given standard.
You can find OSHA approved NRTL at:
Nationally Recognized Testing Laboratory Program.
You can find OSHA approved Standards at:
Appropriate Test Standards
Now you need to find out what NRTL is accredited to use a given standard. You can do that by going to the 1st link, clicking on one of the Lab "MORE" buttons, and then the link that says "Recognized Testing Standards". This will show a page of the standards OSHA has accredited them to use.
Next you're going to have to get a quote from an NRTL to do the testing, which is where the headaches start. Based on my experience, you'll be dealing with a sales person who knows little to nothing about what standard you need to test to. You'll be given a form to fill out (which you may or may not understand)so they can give you a price. Ask to speak with an engineer and have them explain why you need to use the test standards they're recommending. Make sure you have a copy of that referenced standards.
You need to be careful about what they recommend as for one client they wanted to perform a series of test which weren't required because they didn't understand several of the referenced standards.
With regard to "Grounding",
NFPA 70 is the "Electrical Installation Code" adopted by most US States and you can read it on line as well as buy a PDF copy of it. Chapter 2 addresses "Wiring and Protection", and article 250 addresses "Grounding and Bonding", based on the fact that your above 50 volts, you'll need to do something. Remember this in an installation standard, not a manufacturing standard and other codes will have jurisdiction.
You may also want to have a look at the US building codes (
International Code Council) as you may need some form of fire protection on you're product. If so, you'll need to make sure that the product is NRTL Approved, which will likely mean you'll need to coordinate with someone in the US.
Regards,
DM
"Real world Knowledge isn't dropped from a parachute in the sky but rather acquired in tiny increments from a variety of sources including panic and curiosity."