Starter unit any ideas

cliffed · Jul 23, 2021

The grey connection to the lower left..it’s on a starter control box for up & down.

James · Jul 23, 2021

Not sure what the question is?

looks like a control box for a roller shutter door?

cliffed · Jul 23, 2021

James said:
Not sure what the question is?

looks like a control box for a roller shutter door?

The grey connection is it really L & N it’s all working & been install for ages.
This is the isolator for that unit .

timhoward · Jul 23, 2021

I see what you mean.
It looks like you have three phase plus blue marked as Earth coming in.

And I think it’s a single phase supply needed.
And you are (rightly) questioning whether the N for the load is connected to Earth not N.
I had similar recently and you need to check the other end and see how the blue conductor is actually connected.

Mikegh · Jul 23, 2021

The earth seems to be taken off the tag

Neutral wired direct and a phase off the isolator

westward10 · Jul 23, 2021

Existing three phase supply repurposed for single phase but as above check the blue connection at source.

cliffed · Jul 23, 2021

westward10 said:
Existing three phase supply repurposed for single phase but as above check the blue connection at source.

Blue connection was connected to the Earth…that’s the dangerous bit…but is the grey connection block for L/N it’s got a resistor in …just don’t seem correct …obviously installed by the motor specialists..

Mikegh · Jul 23, 2021

Do you.mean the circuit conductors were basically L-E at source with an additional earth taken off the tag

brianmoooore · Jul 23, 2021

So it's single phase, working of one phase of a three phase supply and the earth wire?

westward10 · Jul 23, 2021

cliffed said:
Blue connection was connected to the Earth…that’s the dangerous bit…but is the grey connection block for L/N it’s got a resistor in …just don’t seem correct …obviously installed by the motor specialists..

Why is blue connected to earth dangerous, as long as it is identified and at earth both ends. See this all the time where a three phase supply is repurposed.

brianmoooore · Jul 23, 2021

westward10 said:
Why is blue connected to earth dangerous, as long as it is identified and at earth both ends. See this all the time where a three phase supply is repurposed.

It appears to be serving the dual purpose of earth and neutral. Marked as earth, but used as neutral.

ElectroChem · Jul 24, 2021

brianmoooore said:
It appears to be serving the dual purpose of earth and neutral. Marked as earth, but used as neutral.

Looks to me like the earth is taken off the armour. The blue is connected straight through to the outgoing wire. I'd say the green/yellow tape is just covering some insulation damage (you can still see exposed copper next to the tape). Still not good.

pc1966 · Jul 24, 2021

I also suspect the green/yellow tape is misleading and used for covering damage or similar, otherwise it only has L & 2*E which is really odd.

That looks like a 4-pole isolator and presumably at one time the blue was in the right-most terminal.

Rough as a badger's...

pc1966 · Jul 24, 2021

Actually given this is for a control switch is it 230V at all?

It might be just a small DC switch to 0V = GND in which case L=control (probably pulled up to 24V by a few kOhm resistor?) and others are 0V/E.

Or even using the armour as 0V/E and then L1 & N as the up/down if two pulled up signals? In that case the presence of the old isolator is even stranger.

timhoward · Jul 24, 2021

It goes to show the importance of labelling to avoid confusion.
I had a suspicious one recently, a three phase 4 pin socket (so 3 phases and Earth) but the Earth pin was connected using blue wire on the supply side of the isolator. The armour was earthed too and it was a plastic isolator.
My fear was therefore any metal shell of connected equipment might have been connected directly to Neutral at the CU.
It turned out to be all fine, and once I pulled the isolator body out there was a single piece of yellow/green tape behind it. There is now some tape where you can actually see it....!