Disconnectors

[Isetech]

From neutrral/earth bonding to safe location for lithium battery installtions, to the disconnecting of "appliances".

Its interesting to see how many interpret the discconnection of what many might refer to as appliances.

If you are a Victron installer, you would be looking at installations on social media with double pole DC fuse disconnectors , some at the inverter, some at each battery and some just not suitable for any brand of inverter.

What do you need to install

Do you need a double pole disconnecting device for every battery or just one for the inverter, or just a single pole disconnector as illutrated in the VIctron manual (by the way they are the leader in the industry any way you look at it).

Do you need a double pole disconnector within 1.5 m of the source of the power, be it a battery or a string of solar panels.

[Isetech]

My understanding is that if you switch off a switch disconnector\isolator, the power should be off at the top or bottom of the "isolator/disconnector", many years ago the old main switch was line at the bottom load at the top, best you do what you have been taught to do and switch off and test, then test again just to make sure.

In all the years I have been an electrician, I have been taught that when you open an enclosure and swtich off the main switch, the power in the box is "off" , this have changed over the years, we have penal seperated by some form of barrier, but now we just have a label on the front cover with a light or buzzer.

But never the power on the top and bottom of the disconnector/isolator when in the "off" position.

It seems this has become the norm and a standard practise in the solar/backup industry, its up to you to check the power and find all the disconnectors to isolate all the sources of power which could result in the power stil lon at the bottom of the isolator.

I have been discussing this with a few people and the responses have been rather interesting.

Could this be why MC4 connectors are used for solar applications on the panels and combiner boxes, and inverters have to go into islanding mode, to create a safer environment for people working on the systems. Just imagine if every solar panel being a source of power required a disconnectors, the solution, an MC4 connector which the live wires cannot be touched by the standard test finger. It could also expelain the voltage used for solar panels (below 50 VDC).

Could this expalian why many of the lithium batteries have terminals which can be removed without hte use of a tool to isolate them from the circuitm without leaving exposed live wires.

YOu will notice inverters which dont have DC switch disconnectors built into the inverter, do have MC 4 connectors at the bottom, comapared to ones without MC 4 connectors, have a DC disconnector mounted on the inverter.

Many lithium batteries have battery terminals which can be removed without the use of a tool, (Sunsynk 5.3 kwhgot this wrong by fitting a cover with screws). you just squeeze and pop of the terminals are made of an insualted material.