Old Crabtree ELCB (voltage operated)

[Lectrician]

I am sure I have (and most likey RF) posted a pic of the crabtree ELCB Voltage Operated trips.

Black, cover top and bottom, about 1.5" wide and 9" tall I guess. Feed into the top, load out the bottom, and two terminals marked E and F (i recall), E for the installations MET, and F for the earth rod.

I have come across an 'RCD' today (current opperated) which is also Crabtree. Not seen one before I do not think. It has the old Crabtree ELCB Voltage Operated trip connected to a sencing coil. the sencing coil being connected to the E and F terminals.

Thought I would share, but not really anything to look at unless you are familiar with the old Crabtree voltage operate ones.

Incidently, the old Voltage Operated ones where often used to isolate only the lives - one pole used for the peak, and the other for the off peak. As the voltage operated types do not monitor current 'flowing to and from' the installation, but looked for voltage on the MEC, this worked fine.

 

[Paul_C]

Anything to indicate the current imbalance required to trip on that unit? From the age, I would guess it's likely around 500mA.

Still plenty of those Crabtree ELCB's (in their basic voltage-operated form) in use around here.

 

[Lectrician]

There was no indciation of the mA rating, but it was working PERFECTLY at 300mA when tested. No idea if it was 300mA or not.

There are loads of the basic voltage operated types around here too, many as part of a peak/off peak install. I must have ripped hundreds out by now.