I noticed that the Z30 comes with a charger that is slightly more powerful than the Z10 charger.
At work we have Z10 chargers but no Z30 charger. Is it safe to charge using the slightly less powerful charger or will it have some long-term impact on my Z30 battery?
All it's gonna happen is a slightly slower charge.
You can use any BlackBerry charge with any BlackBerry device, they are all compatible. I personally use the PlayBook one (yellow micro usb connector) that is sold as a generic Premium BlackBerry Charger (5V - 2A output).
Yes, it will be safe. It will just take longer (how much longer depends on how much "weaker" the Z10 charger is,) but it won't do any harm to your battery.
I've noticed that my Z30 charger charges at the same rate as my PlayBook charger according to The Battery Lover app. I also felt that my 9900 would last longer if I charged it with its charger than the PlayBook charger.
I mainly use my 9900's charger for my Z30 over night.
Yeah, I've generally heard that a slower charging rate allows for better battery health in the long-term so long as it has the minimum power requirements to at least allow it to not drain or remain stagnant under heavy usage..