Wiring Diagrams included with industrial electrical design packages

[mull982]

I'm curious how many people see wiring diagrams included in electrical design packages in the industrial arena. When I say "wiring diagrams" I am not talking about schematics with ladder logic etc.... but rather point to point wiring diagrams that instruct the contractor exactly where to land each control cable on designated device terminals.

From what I typically see, I do not see a lot of these "wiring diagrams" included in design packages and its left to the contractor to connect all the control wiring based off of schematics in ladder logic format. I have seen jobs where this can be a large burden for the contractor as sometimes schematics don't directly translate well to connecting wires and can be difficult to interpret what lands where, or in the case where devices are jumpered its difficult to tell where the actual wire should land. I have seen contractors "kick and scream" when they've had to interpret schematics for large industrial projects rather than have point to point wiring diagrams.

I curious to hear what others have seen or dealt with and hear others thoughts on the importance of point to point wiring diagram that show the contractor exactly where to land wires without having to try to interpret schematics.

 

[Smart $]

I haven't seen a point to point wiring diagram in perhaps 20 years. Closest and best I've seen since was cabinet terminal board, wire, and cable layouts with identifiers for each. Every once and a while I may see both ends on same drawing... but I'd have to really tax my memory to see if that's not a total fabrication.

 

[don_resqcapt19]

As an electrician, I have zero use for point to point wiring diagrams...they are a huge pain to work with. If you want to give me something that is useful, give me a spread sheet that shows the termination points at each end of each conductor. I would often make spreadsheets for my guys to wire from.

I often see conduit and cable schedules that tell me the number and size of conductors between various pieces of equipment, but they don't show or give any information on the terminal connections.

 

[Jraef]

When I changed to being an Engineer, I was shocked to see so little attention paid to making wiring diagrams instead of just (ladder) schematics. I brought it up to my boss, he gave me a "don't bug me" look over the top of his glasses. That was in the '80s... I haven't seen more than a dozen a point-to-point wiring diagrams on a project since then. Every now and again I see one on an OEM piece of equipment, mostly when a project spec requires them. But consultants I work with now don't require them any longer, or if they do, are unaware of the difference and accept the schematics as if they are wiring diagrams. I think the concept has become muddled now.

 

[don_resqcapt19]

In the past a lot of OEM equipment only had wiring diagrams....it is my opinion it is much more difficult to troubleshoot from a wiring diagram than it is from a schematic.

 

[petersonra]

Point to point diagrams are much harder to create. Schematics are simpler and easier to use for most people who have familiarity with them.

We charge extra for point-to-point diagrams because not only do they cost more to create but it also adds wiring time.

The place I used to work often produced such drawings, and it always annoyed the shop because it is very hard to make that work up front and there are often a lot of patches that have to go into it along the way.

It is a little different if it is an MCC section or something similar where a bazillion of the same thing is being made but for something one off it is a pretty good chunk of change.

In fairness, back in the day very few field electricians could read schematics and were just plain unable to wire unless they were given point-to-point diagrams. These days, I almost never run into that problem.

 

[Bugman1400]

In the utility industry, the spreadsheets just don't work. When, each control panel has dozens of 24-conductor cables and then tons of SIS intra-panel wiring, a point-to-point is essential.

 

[smoothops10]

It is generally notpossible in a design-bid-build job. The specifications may name multiple manufacturersand or equals for equipment each with their own control system. The purpose ofthe bid documents is to provide a code compliant and safe design that can bebid. The circuit schedules with quantity, size, and distance provide just that.Knowing where to land conductors inside panels and field instruments generally cannotbe known until after shop drawings are submitted and approved.

 

[gadfly56]

In the utility industry, the spreadsheets just don't work. When, each control panel has dozens of 24-conductor cables and then tons of SIS intra-panel wiring, a point-to-point is essential.

I've done fire alarm projects in three electrical generating stations. Every one required a point-to-point list, including any intermediate junction boxes. Creating them was NOT my favorite part of any of those projects.

 

[mull982]

Some interesting responses here and I appreciate them all. I myself am not a contractor and my comments/questions are coming from my experiences as a project engineer for an owner/customer who has been involved in several large project. I have recently transitioned into more of a design role and was curious hear all these comments related to wiring diagrams.

As an electrician, I have zero use for point to point wiring diagrams...they are a huge pain to work with. If you want to give me something that is useful, give me a spread sheet that shows the termination points at each end of each conductor. I would often make spreadsheets for my guys to wire from.

I agree as an end user or electrician wiring diagrams don't help much in terms of troubleshooting nearly as much as a schematic does. But I'm thinking more along the lines of assisting the contractor with the initial installation where going through multiple pages of schematics could be a daunting task to determine which wires land where. I suppose spreadsheets can serve a purpose for assisting the contractor with wiring but that still puts the burden on the contractor to comb through the schematics to develop this spreadsheet. Perhaps however that is just the accepted responsibility of contractors and my thinking of this being the engineers responsibility was backwards.

I often see conduit and cable schedules that tell me the number and size of conductors between various pieces of equipment, but they don't show or give any information on the terminal connections.

This too is what I have typically seen in other design packages. A cable schedule or control riser diagram showing the to and from of cables and conduit but no information on the actual terminations.

In the past a lot of OEM equipment only had wiring diagrams....it is my opinion it is much more difficult to troubleshoot from a wiring diagram than it is from a schematic.

I'm assuming here that your saying that OEM equipment had a wiring diagram strictly for the wiring within that piece of equipment in the drawings provided by the OEM, however the project construction design drawings do not have wiring diagrams for the interconnection of the wiring between these various pieces of equipment.

Point to point diagrams are much harder to create. Schematics are simpler and easier to use for most people who have familiarity with them.

We charge extra for point-to-point diagrams because not only do they cost more to create but it also adds wiring time..

I agree that they take longer to create than simply creating the schematic which has to be created anyway. The wiring diagrams are usually just an extension of the schematic. I suppose a schematic can be used along with the cable schedule to assist with wiring in that the schematic can have wiring tags on the schematic that correspond with the cable schedule so that the schematic would act as sort of a schematic/wiring-diagram hybrid.

It is generally not possible in a design-bid-build job. The specifications may name multiple manufacturers and or equals for equipment each with their own control system. The purpose of the bid documents is to provide a code compliant and safe design that can be bid. The circuit schedules with quantity, size, and distance provide just that. Knowing where to land conductors inside panels and field instruments generally cannot be known until after shop drawings are submitted and approved.

This is a very good point and perhaps one that I overlooked. I guess for this type of project as stated, it is unknown at the design stage which equipment will be chosen so it is impossible to provide point to point wiring diagrams as the final type of equipment chosen may vary. These are the type of design packages I am used to seeing where I guess the final equipment is unknown so all that can be provided in the design is the to-from and the number of cables. I usually see "typical" schematics along with these packages.

I'm curious in this situation how this is handled during the construction phase. After equipment is selected and being installed who determines how it is wired and to which terminals if this information is not in the design package. Is this again just an assumed responsibility of the contractor?

If the project is one where the equipment is known ahead of time should the designer at least make an attempt to provide some sort of wiring diagram, or now adays is the schematic considered sufficient for the contractor to use for installation?

 

[don_resqcapt19]

In the utility industry, the spreadsheets just don't work. When, each control panel has dozens of 24-conductor cables and then tons of SIS intra-panel wiring, a point-to-point is essential.

That is exactly the type of installation where I much prefer spread sheets. Much easier for the installer to use and understand. The spread sheet will tell you the cable number, the number or color of the conductor within the cable and the termination points at each end of the cable.

Note that I don't do utility work, but similar industrial projects with large DCS or PLC systems and multiple conductors and or cables. My typical marshaling panel installation would have multiple 2" conduits and each conduit would have three 40 conductor bundled sets of #14 or 16 conductors (digital) or three 15 pair shield cables(analog).
The largest marshaling panel I worked on had about 30 digital conduits and 20 analog conduits. This was wired 100% from spread sheets.

 

[mull982]

For the sake of this conversation I have attached what I am referring to as a typical point-to-point "wiring diagram that shows where the wire lands at both ends.

I suppose the other version of this could be a drawing which shows the terminations of one end of the cables in a cabinet and another drawing that shows where the other end lands in the respective cabinets. Each cabinet or piece of equipment would have its own wiring diagram showing terminal blocks where each cable landed I that cabinet with a cable tag that could be used to reference the same cable in another drawing which corresponded to the equipment where the other end of the cable lands.

I have just seen projects where the schematics can be 100+ pages of schematics in an industrial plant which can make it cumbersome to tell how with wiring is routed.

One example is a plant that I worked at where the schematics show a bunch of devices wired on the same circuit so the hot's and neutrals were jumpered in the field. From a schematic its difficult to tell how these are jumpered in the field in what order which can make it difficult to troubleshoot. A wiring diagram would show this info.

 

[gadfly56]

For the sake of this conversation I have attached what I am referring to as a typical point-to-point "wiring diagram that shows where the wire lands at both ends.

I suppose the other version of this could be a drawing which shows the terminations of one end of the cables in a cabinet and another drawing that shows where the other end lands in the respective cabinets. Each cabinet or piece of equipment would have its own wiring diagram showing terminal blocks where each cable landed I that cabinet with a cable tag that could be used to reference the same cable in another drawing which corresponded to the equipment where the other end of the cable lands.

I have just seen projects where the schematics can be 100+ pages of schematics in an industrial plant which can make it cumbersome to tell how with wiring is routed.

One example is a plant that I worked at where the schematics show a bunch of devices wired on the same circuit so the hot's and neutrals were jumpered in the field. From a schematic its difficult to tell how these are jumpered in the field in what order which can make it difficult to troubleshoot. A wiring diagram would show this info.

The first time I ran into this type of drawing was at one of the power plants I mentioned. On my projects, it was all descriptive and laid out as tables. If I can find a pdf I'll upload it.

 

[JoeStillman]

It is generally notpossible in a design-bid-build job. The specifications may name multiple manufacturersand or equals for equipment each with their own control system. The purpose ofthe bid documents is to provide a code compliant and safe design that can bebid. The circuit schedules with quantity, size, and distance provide just that.Knowing where to land conductors inside panels and field instruments generally cannotbe known until after shop drawings are submitted and approved.

I agree with Smoothops. As a consulting engineer, I am trying to represent the owner the best I can. That usually means non-proprietary specifications (A, B, C or equal). To spend so much effort on a basis-of-design manufacturer that only has a 25% chance of getting the job is usually a big waste of time; you wind up with useless drawings that someone is trying to build with.

I can do a much better job when I get hired as a "System Integrator" - doing point-to-points after the vendors are selected. Then we can sort out all the interconnections between various manufacturers that have no interest in talking to each other. This is rare though.

 

[petersonra]

If a customer is willing to pay extra for it we will make any kind of drawing they want.

 

[Tony S]

Like most others I dislike point to point drawings, I hate having to produce them. Other than the most basic things I use schematics and spreadsheets in the hope the electrician knows what he/she is doing.

Spreadsheets for cable schedules and final terminations on major jobs are esential.
The cabling contractor doesn’t need to know what does what, just where to terminate cables. Hopefully in the right order.

 

[JoeStillman]

Like most others I dislike point to point drawings, I hate having to produce them. Other than the most basic things I use schematics and spreadsheets in the hope the electrician knows what he/she is doing.

Spreadsheets for cable schedules and final terminations on major jobs are esential.
The cabling contractor doesn’t need to know what does what, just where to terminate cables. Hopefully in the right order.

The electrician may not want to know what does what, but I do. I need the diagram to be sure it's all going to work.

I saw a plug-in for AutoCAD once that makes tables (like spreadsheets) from the diagrams.

 

[mull982]

I appreciate all of the feedback, this is good information.

Does anyone have an example of a point to point spreadsheet that they have created or seen that you are able to share. I'm curious to see what one of these looks like in comparison to a wiring diagram.

For a Design-Build project do you feel that the burden should be on the designer for creating these spreadsheets or wiring diagrams, or is that still the responsibility of the integrator or contractor?

Are integrators typically a third party for most projects, or does the design engineer usually come back to be involved in the integration process?

 

[petersonra]

For a Design-Build project do you feel that the burden should be on the designer for creating these spreadsheets or wiring diagrams, or is that still the responsibility of the integrator or contractor?

If someone wants a spreadsheet or for that matter anything else that is outside the requirements conferred by the contract, it seems to me it is up to whoever wants it to pay for it. I don't really understand how a so called "design-build" situation would change whatever the contractual obligations are. Something is either contractually required or it is not. I have not seen point to point diagrams required in a contract in at least a decade.

Are integrators typically a third party for most projects, or does the design engineer usually come back to be involved in the integration process?

I don't know what you mean by a "third party". It is a part of the project like any other part of the project. Stuff gets bought piecemeal at the lowest possible cost and then somehow gets glued together into a useful system. To me that is what "design-build" means, because that is what it generally ends up being. The controls integrator is there to see that all the stuff can be controlled somehow. Often the "design-build" contractor is completely clueless about what is actually needed to make the stuff work with the rest of the plant so you end up with a lot of wires going back and forth. I wish they would just buy the Ethernet interface, then most of the wiring would just go away, but it often adds $50 to the cost so the "design-build" people will leave it out because integration is not part of their contract. That decision might add $1000 to the cost of the project overall, but the "design-build" people saved themselves $50.

 

[wireman]

If a customer is willing to pay extra for it we will make any kind of drawing they want.

I work for a system integrator and as long as we're getting paid to do it we also make any kind of drawing they want.
Most of what we do are one of a kind projects and we do not know how the electrical contractor is going to run his conduits or trays. Also we don't know if they are going to install a JB with terminals to use as an intermediate point. Without knowing this it is almost impossible to provide good point-to-point drawings.

At the beginning of the project I like to get with the electrical foreman or whoever and go over our drawings. This helps immensely to avoid confusion.
Then near the end of the job I like to meet with him and find out what we could do to improve the drawings for the next project I do.

It's amazing on how much it can throw some people if the look and feel of our drawings is different than another companies even though we use standard NFPA/ISA/JIC symbols and abbreviations.

Hopefully others will chime in on this topic. I'd like to hear more.