1.5V is the JEDEC standard for DDR3, therefore you will never fry a module at this voltage.
Hynix: "Hynix DDR3L SDRAM provides backward compatibility with the 1.5V DDR3"
Crucial refers to this as Dual Voltage: In the past, most DDR3 memory voltage ranged from 1.5 - 1.65v. More recently, dual 1.35/1.5 voltage modules came available at Crucial.com. The dual-voltage module will run only run at 1.35V if your specific system supports that voltage, otherwise the memory will run at 1.5V.
Kingston: As DRAM manufacturers shrink their dies and/or increase their yields of DDR3L, they soon reach a point where the majority of their DRAM output becomes DDR3L or dual-voltage, handling 1.5V or 1.35V voltages.
DDR3L (low-voltage DDR3) is just an "extension" of the DDR3 standard, so companies has to be aware that plugging a module will default to 1.5V on most systems. At 1.5V, the worst that will happen will be a waste of electricity/battery.
RAM modules contain pre-defined configurations (SPD, XMP, etc.) but the default one is often safer value that will work on as many systems as possible. For compatibility purposes, that setting might not be factory-set to 1.35V, but 1.5V instead. The default timings can also be different and slower from the ones indicated on your module package (I have an other answer on this topic).
For this reason, there's no chance it will overclock by itself even if it's running at a higher voltage (unless your current BIOS settings are manually set to run at specific speeds higher than your new modules would support - if so, reset your memory settings to AUTO before installing them).
If your RAM contains a XMP profile, try that as it can be factory set to 1.35 and all ideal settings - but you still have to select it manually in the BIOS.
In conclusion, 1.35V is perfectly safe. It's still always a good idea after installing RAM to go in the BIOS and verify/adjust the settings to ensure they match the module packages and perform optimally.