When I run
Get-WmiObject win32_SystemEnclosure -Computer hostname | select serialnumber
it works for both local and remote hosts.
W
I was having the same problem but only with a few machines. I found that using Invoke-Command to run the same command on the remote server worked.
So instead of:
Get-WmiObject win32_SystemEnclosure -ComputerName $hostname -Authentication Negotiate
Use this:
Invoke-Command -ComputerName $hostname -Authentication Negotiate -ScriptBlock {Get-WmiObject win32_SystemEnclosure}