What Does an Orange Wire Do in an Electrical Control Panel?


▶ Check out the full blog post over at


Within the panel, we have a number or orange-colored wires. You may wonder what these are for, as we’ve already heard of the blue and white wires connected to the PLC.

Well, what these wires are for is to give power to devices when the main switch or panel isolator is in the OFF position.
“Why would we want to keep things on when we’ve turned the power off?” I hear you ask! “Isn’t that dangerous?” Well to put it simply, NO!

If we try to understand the different colored wires in a panel, this will help us to understand why those that are colored orange are suitable to work even when the main switch is off.

The colors of wires in panels are required by law to follow the machine safety standard EN60204-1. This is so that there is consistency and for safety.

In Power Circuits – AC and DC – we have the following color coding;
AC Phase will be BLACK
AC Neutral will be LIGHT BLUE
DC+ will be BLACK
Earth will be GREEN YELLOW

In Control Circuits – AC and DC – we have the following color coding;
AC live will be RED
AC Neutral via transformer will be RED
AC Neutral (mains) will be LIGHT BLUE
DC+ will be BLUE

Interlocks and circuits supplied from remote panels will be ORANGE – in this case, not the one we’re after!

Earth will be GREEN YELLOW

Panel services are 240VAC supplies for panel internal lighting, programming console socket outlet, internal heating & cooling, CPU’s (memory backup purposes), etc.

These are ‘excepted circuits’ as defined in EN60204-1 and as such are not disconnected by the main panel isolator but by a separate isolator mounted inside the panel and designated ‘maintained supply’.

The color coding for multicore cables;
Sheath will be ORANGE
AC live cores will be ORANGE
AC neutral cores will be ORANGE
Earth cores will be GREEN YELLOW

Color coding for single-core cables;
AC live will be ORANGE
AC neutral will be LIGHT BLUE
Earth will be GREEN YELLOW

So we come back to the original question…what wires in our panel are orange?

Well, firstly we have the panel internal light. We want to be able to see when we turn the main switch off!

Next, we have the socket. This will allow us to keep our laptop charged up. If the panel needs to be turned off for an extended period of time, then when we are ready to go, our laptop may have died. Not good! The socket is protected by a fuse so that any spikes in power won’t damage our laptop!

The final thing we have in this panel with power is a topic we’ve already covered; the thermostat and cooling fan!

As we’ve already determined, we need to be able to keep the panel cool, even when the main switch is off.

So how does this all work? Well inside the panel, we have the mains feed 3 phase power that comes into the panel to a set of terminals labeled L1, L2, L3, and N.

You can see from this that 1 phase – L1/N –has orange wires in. It is separate from the other wires in this terminal block so that they act independently.

On the back of the main switch on the left-hand door, the wires are identified as L1, L2, L3, and N, matching what we have on the terminals.

The outgoing side of this main switch will be isolated if the switch is off, and will be powered if the switch is on. The main switch is connected to the contactor labeled “150K1”.

When the switch is on, giving power to the panel, this contactor will be “pulled in” or “energized”. Once this is energized, power can be distributed around the rest of the panel.


If you want to get in contact with Pro-control, you can check out their website over at https://www.pro-control.nl/


Missed our most recent videos? Watch them here:





To stay up to date with our last videos and more lessons, make sure to subscribe to this YouTube channel:



TWEET THIS VIDEO https://ctt.ac/FWus4


Like us on Facebook: https://www.facebook.com/therealpars/

Follow us on Twitter: https://twitter.com/realpars

Follow us on LinkedIn https://www.linkedin.com/company/realpars

Follow us on Instagram https://www.instagram.com/realparsdotcom/

#RealPars #PLC #ControlPanel