DIN Rail Terminal Blocks: L/L, L/N, N/L and N/N?

[Purple_Dan]

Hello,

I've recently had a slight trajectory change in my career and I'm learning the ropes in electrical panel building.
I have to order a load of DIN rail terminal blocks and I've come across a few variants and I don't know which one is the correct one for my application, or if it even matters.

I understand that the L and N stand for live and neutral, I'm not a complete rookie, but in terms of double deck DIN rail terminal blocks, what's the difference between L/L, L/N, N/L and N/N?

Any help is greatly appreciated, and sorry if a similar question has been posted before, I couldn't find any information about this anywhere!

Thanks,
Dan

 

[berkeman]

Hello,

I've recently had a slight trajectory change in my career and I'm learning the ropes in electrical panel building.
I have to order a load of DIN rail terminal blocks and I've come across a few variants and I don't know which one is the correct one for my application, or if it even matters.

I understand that the L and N stand for live and neutral, I'm not a complete rookie, but in terms of double deck DIN rail terminal blocks, what's the difference between L/L, L/N, N/L and N/N?

Any help is greatly appreciated, and sorry if a similar question has been posted before, I couldn't find any information about this anywhere!

Thanks,
Dan

Are you an apprentice to an electrician now? What sources of information are you using to learn this trade? Are you in the US, and if so, do you know what the NEC is?

Also, can you provide some links to the DIN Rail modules you are asking about?

 

[Purple_Dan]

Are you an apprentice to an electrician now? What sources of information are you using to learn this trade? Are you in the US, and if so, do you know what the NEC is?

Also, can you provide some links to the DIN Rail modules you are asking about?

Hello, I'm not an apprentice, I'm a qualified controls engineer and have been working with mainly software for 2 years now.
I'm familiar with the principals of electricity, but not all the tools that are used in the industry.
This is my first experience with panel building, but I've worked with electrical panels before, just checking I/O to the PLC usually though.
I'm using a mix of Google and professional advice from colleagues. However, the other 2 electrical guys that work here are usually on site somewhere, so I have limited access to their expertise.
I'm situated in the UK, our NEC is in Birmingham, I think Crufts is there soon. I expect that's not what you meant.

I was looking at the following catalogue: http://www.wago.us/media/us/collection/brochures/topjobs.pdf
If you look at any of the double/triple deck terminals (Page 37, for example), then you'll see that you can specify L/N, N/L, etc.
Just wasn't sure what that meant exactly. I would've thought that whether it was L/L, L/N or N/L would depend entirely on what's connected to it!

Thanks for your input!

 

[berkeman]

I'm going to tag @anorlunda to see if he can help on this question. I looked at the catalog, and it's not obvious to me why you would use one version over the other.

I'm situated in the UK, our NEC is in Birmingham, I think Crufts is there soon. I expect that's not what you meant.

I was definitely asking about something else...

http://cdn1.bigcommerce.com/server4200/08a4wlo/images/stencil/1000x1000/products/13916/59655/100_1082__81086.1385146106.JPG?c=2

 

[anorlunda]

L/L, L/N, N/L and N/N

Sorry, not my field of expertise either.

 

[GrahamN-UK]

> do you know what the NEC is?

In this context the NEC is the US National Electrical Code:
https://en.wikipedia.org/wiki/National_Electrical_Code

It's the US equivalent to the UK's IET Wiring Regulations or, more formally,
BS 7671:2008+A3:2015 (17th edition with Amendment 3:2015)
https://en.wikipedia.org/wiki/BS_7671

You (or at least one of your 2 electrical colleagues) should be familiar with
the 17th ed. The IET has a list of recognised training providers at:
http://electrical.theiet.org/training/index.cfm

I attended a 3 day wiring regs course some time ago. It was rather a whirlwind
tour but it did provide a useful introduction to a large and complex standard.

> If you look at any of the double/triple deck terminals (Page 37, for example), then you'll see that you can specify L/N, N/L, etc. Just wasn't sure what that meant exactly. I would've thought that whether it was L/L, L/N or N/L would depend entirely on what's connected to it!

L=Live, N=Neutral, PE=Protective Earth, of course.

The terminals in the catalogue are colour-coded: L=grey, N=blue, PE=green/yellow.

The idea is that you, as the designer, choose the colour of terminal to suit the
use of the conductors running through the terminal. This let's installation and
maintenance staff know what type of conductors they are dealing with and makes it
easier to find their way round a huge number of terminals side by side.

I expect the N/L and L/N terminals have the upper contacts in one colour and the
lower contacts in the other colour. I can't see from the catalogue which is which
but as a customer you could ring the helpline and ask. You ought to choose one or
the other of N/L or L/N and use that option for all your panels to avoid confusing
installation and maintenance staff. (If your company already has a standard choice
obviously you should stick with it.)

Although this again is not my field, good practice suggests that you should use the
double terminals for the two sides of a single (1 phase) circuit, i.e. use one
double terminal to carry the L & N for a single load circuit; don't mix and match
random L and N wires from different circuits on the same double terminal.

I found an introductory video at:


(For US readers, in the UK 'NEC' refers to our National Exhibition Centre, a large
exhibition and conference venue in Birmingham: http://www.thenec.co.uk/ )

 

[rbelli1]

I expect the N/L and L/N terminals have the upper contacts in one colour and the
lower contacts in the other colour.

Yes. I had found a picture that shows this and thought I posted it but it seems to be gone. One or more of the wire openings have a painted color around them. You can just barely see this in the catalog.

BoB

 

[Purple_Dan]

> The terminals in the catalogue are colour-coded: L=grey, N=blue, PE=green/yellow.

The idea is that you, as the designer, choose the colour of terminal to suit the
use of the conductors running through the terminal. This let's installation and
maintenance staff know what type of conductors they are dealing with and makes it
easier to find their way round a huge number of terminals side by side.

I expect the N/L and L/N terminals have the upper contacts in one colour and the
lower contacts in the other colour. I can't see from the catalogue which is which
but as a customer you could ring the helpline and ask. You ought to choose one or
the other of N/L or L/N and use that option for all your panels to avoid confusing
installation and maintenance staff. (If your company already has a standard choice
obviously you should stick with it.)

Yes. I had found a picture that shows this and thought I posted it but it seems to be gone. One or more of the wire openings have a painted color around them. You can just barely see this in the catalog.

BoB

Cool, thanks guys.
Sorry for the late reply, I've been quite busy on other projects.
But good eye, didn't spot that!