Terminal Strip VS Power Distribution Block

[davidr43229]

The things we think about, when we shower in the morning...
When does a Terminal Strip stop being a Terminal Strip and become a Power Distribution Block?
Is is UL1059 vs UL1953?
Is it amperage driven? If the Terminal Strip carries 200-400amps?
Is it voltage driven?
Are the UL listings the same?
Just my $.02

 

[petersonra]

A terminal strip can be used as a PDB, it certainly is pretty common to do so, at least at lower amperages.

 

[ECE2001]

The things we think about, when we shower in the morning...
When does a Terminal Strip stop being a Terminal Strip and become a Power Distribution Block?
Is is UL1059 vs UL1953?
Is it amperage driven? If the Terminal Strip carries 200-400amps?
Is it voltage driven?
Are the UL listings the same?
Just my $.02

I don't believe the UL listings are the same.
Click on the link below to see the scope of 1059, I could not find the scope of 1953, but 1953 is referenced in 1059.
UL 1059

 

[davidr43229]

UL1953 is the new standard for UL508A for spacing within the feeder circuit.


....................Betweeen live parts....................Between live parts and
...................of opposite polarity.....................Grounded metal parts.
VOLTAGE........Through AIR....Over surface.........through air & over surface
125 or less......1/2"..............3/4"......................1/2".............................
126-250.........3/4"..............1 1/4"....................1/2"............................
251-600.........1".................2".........................1/2".....................

Standard Power Distribution Blocks & Terminal Strips do not have this spacing requirement, when used in the feeder circuits within an Industrial Control panel.

 

[sandsnow]

Here's my two cents:

Why are there not any clearances for the grouned conductor to grounded metal? That is after the main bonding jumper.

Why are there not any clearances between primary and secondary voltages in a xfmr? or is this considered opposite polarity?