THere are two types of hacking method to get TP Preview for phones...

[geoghotas]

Finally: Install Windows 10 for Phones on No… | Windows Phone 8 Development and Hacking | XDA Forums

[????100%??]??????????????WP10?? - Windows 10 Phone????? |WP10??|Win10??|???

 

[Akash Patel]

Finally: Install Windows 10 for Phones on No?€? | Windows Phone 8 Development and Hacking | XDA Forums

[????100%??]??????????????WP10?? - Windows 10 Phone????? |WP10??|Win10??|???

both are the same the first one is translated version of the later one

 

[Harrie-S]

Finally: Install Windows 10 for Phones on No… | Windows Phone 8 Development and Hacking | XDA Forums

[????100%??]??????????????WP10?? - Windows 10 Phone????? |WP10??|Win10??|???

So now you must have the windows 10 preview on your phone.
Please let us know how you like windows 10 preview on your 1520.

 

[I3unny]

Is it safe??

 

[boltman2013]

Is it safe??

Until an update gets pushed most likely

 

[I3unny]

I would like to wait for Microsoft to push the update

 

[Akash Patel]

Is it safe??

It is not like preview for developer version the preview for developer was a polished version and this one is a typical beta release
You shouldn't try it if it is your primary device as there are bugs.

 

[xandros9]

Is it safe??

If you have to ask, don't do it.