Numbering terminal blocks

godfrey

Member
Join Date
Apr 2002
Location
Charlotte, NC
Posts
412
When numbering terminal blocks, is it OK to use a number for a terminal that passes neutral or should it be marked N? I am putting togethr a terminal strip for field wiring of terminals. The strip passes power to solenoids. The solenoids are 110VAC. My terminals go hot, neutral, ground, hot, neutral, ground and so forth down the line. I was considering a scheme where the terminals were numbered consecutively like 200, 201, 202, 203, 204... and so forth. Or should it be 200, N, E, 201, N, E...?
 
Hi there,

I'm building panels, and i number the with a number.
Sometimes when i have a power supply through the terminals i use the "n". As long its marked rigth on the drawings, i think no one has a problem.
 
I always use different color blocks for that reason: red, white, yellow/green ground block, red, white, yellow/green ground block, etc. Then you just label the red blocks how ever your number system goes, and label all the white ones L2....I find this to be the clearest way to do it.
David
 
While it makes troubleshooting a little simpler to have the common labled the same throughout, IE: 2 or 4 or N, as long as the terminal designations match the schematics I see no problem.

You would make wiring the panel simpler by putting all the commons side by side. This would allow you to install factory tstrip jumper one time.
 
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There's enough equipment where I work that you could probably find any of the schemes mentioned if you look long enough. My personal preference is for the ones which label hot and common as X1 and X2 respectively. This makes them more noticeable both by their brevity and the 'X', which sets them apart from pure numbers. Wires for series E-stops are numbered sequentially starting from the drawing line of origin. PLC I/O is numbered to match the I/O terminal address.
 
I am glad this came up

I am building panels now (one so far with second in the works) and like knowing all the different ways its done.

At this time with both 120vac control and 24vdc I use group of common terminals for each...ie X1 is 120vac and its tied to a group of bonded terminals, X2 tied to group of bonded terminals, 24vdc is labeled 24vdc and 0vdc. This way whether feeding into the cabinet or out its the control voltages are connected at a common point.I am using the larger Square-D 9080 terminals right now that have a place to designate wire number or ? and I also use a small label printer and label the groups accordingly...ie 120vac, Neutral, 24vdc, and 0vdc. This small label printer allows me to print to varying lengths so I can adjust it to what length I need. I label everything.

I am having a bigger issue with wire color convention, this plant in the past has used BLUE to designate 24v... 24vac or dc whether hot or common...both wires are blue. Devicenet confuses the issue even more designating black and red for their 24vdc wires.
 
Try and simplify the life of the next person to troubleshoot the panel WITHOUT THE DRAWINGS.

When they are marked N its very easy to figure what they are.

If the wires are white its even easyer.

204 don't tell you much.

When using X1 and X2, one look at the x-former outgoing fuses will give the guy a hint but as far as neutral goes, since there is a way to make cristal clear, why not using it?
 
godfrey said:
My terminals go hot, neutral, ground, hot, neutral, ground and so forth down the line...numbered consecutively like 200, 201, 202, 203, 204... and so forth. Or should it be 200, N, E, 201, N, E...?

Typically, when "doing" wire numbers, a wire shouldn't change numbers unless it electrically changes (passes through a contact, etc.) I would (and do) make neutral=2 and ground=gnd all throughout the project, unless there are multiple control transformers, because they are logically the same wire. In the case of multiple control transformers the neutral would typically be labeled 2a, 2b etc. depending on which transformer it came from, and ground would still be gnd.
 
I agree with 93It1. All my neutrals are the same number, generally 2. I think it is bad practice to use different numbers for wires that are electrically identical.
 
godfrey said:
When numbering terminal blocks, is it OK to use a number for a terminal that passes neutral or should it be marked N?

IMO, either method is perfectly acceptable. As 'rocket man' mentioned, it will be a lot easier if you use multiple level blocks. You can get triple level blocks with the bottom tier self-grounding (in green/yellow, too!) specifically for things such as solenoids, etc... :nodi:

HERE'S an example from Entrelec.

Multiple tier blocks will also take up a LOT less space!... (y)

beerchug

-Eric
 
please use X1 for numbering terminals related to each other as cables or as usage like all sensors on X12 motors on X5
one sensor has a number and will be on a page in the drawing so why not use its number. so general number can be X12-20.5 and for the N or L: X12-20.5N, X12-20.5L
this way i can turn to the page immediatly. my program does this automaticcally (caddy) not turning page but numbering)

as aid you can use colored terminals
Do not pack all N terminals together or not number them as someone that must all sensors will not do them nicely on the terminals designated but will leave all blue wires up to last and then connect them just on any terminal making it very difficult afterwards to find a fault.
I also never use ground terminals but connect them on an isolated bar, so i can find ground faults. as i do a lot in analog sensors i always leave one side open to avoid ground loops. and the other side i need for test.
 

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