Had it installed earlier today by a communications company. Techs said it would be safe because the antenna is grounded well enough... Should I have the wire grounded as well before I start using it?
Wow, not sure where to start with this.
Yeah, some installers cut corners, and they'll tell you it's "OK".
"OK" means different things to different people.
To some, OK means: No one died in the installation and it didn't cost me a lot.
To others, OK means: it was done well enough and I got what I think I paid for.
To others, OK means it was done correctly, to code, and there's no questions about it.
In the hobby realm, it's going to be one of the first two in most cases. Scanner listeners, SWL, amateurs, most of them never bother to ground anything. If they don't get a shock and their house doesn't burn down, that's considered OK.
In the professional realm, it's going to be the last two. Some installers will cut corners and call it good as long as they don't have to work late, miss lunch, get the boss mad at them, etc. Other installers know that they could be liable if they did the install incorrectly and someone was hurt, the house burned down, or an inspector would find fault with the installation.
What the installer did for you was take your money, do a halfway install, and while he did "ground" it, he didn't do it correctly. What he did would absolutely not pass an inspection. It does not meet the NEC. Your homeowners insurance might even take offense to it if there was damage to your home or a person due to this install. That might result in them not paying out, or they may not care.
Either way, it's not done to code, and that should be enough discussion.
But it won't.
Like I said, many people just stick the antenna up in the air and call it good.
Yes, you might not have any issues at all. No damage, no injury, no problem.
You might have noise issues. You might damage your radio from static electricity, a house wiring fault, a nearby lightning strike, etc.
In reality it comes down to what YOU want. Are you OK with what was done, or do you want it done to the National Electric Code standard?