Will a 400w power supply be safe where a 250w was

[Ludwikia]

Exactally what the title says: will a 400w power supply be safe to use in a box that came with a 250w stock?

 

[wa1]

Yes, it's very very safe...
Could u give us the model? brand?

 

[shubham1401]

Yes it will be safe.
You can even use a 1000W unit.

Just make sure it will fit.

 

[jay2tall]

Sure as long as it fits in the current location. I would have the same ATX power connector and ATC CPU power connector. Some OEM companies like Dell and HP used to use a few proprietary PSU's but I haven't seen one of those in a while.