3phase transformer no neutral?

[paulthe spark]

Just a quick question lads been disconnecting all the temporary power as the site coming to an end and when I was disconnecting the 3 phase 110v transformers there wasn't a neutral present. Just 3 phases and an earth. Was curious why this was as I thought it would definatly need a neutral as people are plugging in lights etc sorry if this is a silly question but has really got me thinking
cheers fellas

 

[bugsy]

Treated as TT supply

 

[mechelec]

Are you saying the supply to the tranformer was three phase and earth? if so then this is correct as the transformer will be wired in deta on the primary side hence no neutral. secondary will be standard 110v CTE

 

[mogga]

having done these for quiet a few sites its as Mech says 100v CTE If your connecting them Id use 4core SWA and use 4rth core as Earth also put an earthclamp( Bad practice I Know ) on armour incase the armour gets pulled out the gland as guys on site dont think about stuff like earths when they are humping trannys around And mind "D" type mcbs

 

[davelerave]

ya 'D' type on the primary

do all the site trafos come with overload protection




fitted two wall mouned trafos lately-came with nothng except the earthlink for the centre tap

fitted the overload protetion at sec DB

i don't understand why online references show overload protection of 125%FLA minimum
http://www.bussmann.com/library/indcon/Power transformer protection.pdf

supplier said 100%FLA anyhow