There are numerous decisions for a new EPLAN user to make when creating designs using the NFPA convention. In this article I will discuss the various plot frame considerations for NFPA users of EPLAN.
If possible, just forget about NFPA and adopt the IEC standard, almost everything about it is simpler and less time consuming. The IEC standard is an international standard and many companies in the USA are switching over to it now more than ever before. Businesses are putting pressure on engineers to comply with international standards to bring down costs and to simplify design collaborations.
EPLAN was designed to work with symbols with an 8mm pin to pin pitch on an ISO A3 page with no rows and 10 columns, it works very well in the IEC realm.
It also works fine with NFPA designs, but there are several considerations to be aware of.
Plot Frame Size
The first issue we must consider is what size plot frame to use in our designs. EPLAN comes with many sample plot frames but when you look at them through the eyes of an NFPA user, the list of offerings shrinks pretty fast. EPLAN includes sample plot frames ranging in sizes from ANSI A to ANSI E, but most of these sizes are not really useful for electrical engineers. As electrical engineers we have several additional considerations. How do the symbols look on the page? How many rows can I fit on a page? What are the most common libraries in use?
As a new EPLAN NFPA designer you will need to choose which symbol libraries you will use. EPLAN offers the same symbols for NFPA users in either a 1/2 inch or 8mm pin to pin pitch library. These libraries have a fixed pitch and cannot be adjusted. The inch based symbols are physically larger and work best on larger page sizes such as ANSI D & E, while the metric symbols are smaller and work best on smaller page sizes. Once you select a symbol library to work with it is best if you do not mix the symbols from different NFPA libraries in a project, EPLAN can manage them but problems can arise.
The decision on which symbol library to use is often impacted by understanding what symbols are most commonly found in use on the data portal. The EPLAN data portal is a repository for manufacturers data and symbol macros for an ever growing number of commonly used part, Manufacturers create this data so that you don’t have to. At the time I created this document, there were 198 manufacturers on the EPLAN Data Portal and only one of them creates symbols that use the NFPA INCH library (NFPA_symbol_en_US.sdb). OK, it’s a pretty big manufacturer (A-B) but they also have the same parts and many more available with the NFPA mm symbol library (NFPA_symbol.sdb).
Unlike mechanical drawings, electrical drawings have the added burden of naming devices based on where they are inserted into the design or by user schemes. In EPLAN these complex issues are handled via an invisible network of page row paths, device origins and user & project settings.
The page size choice can be impacted if there is a requirement for a certain number of rows per page, there are practical limitations due to the pin pitch of the symbols used. Users can always select to have fewer, larger rows but this can create other complications in use such as multiple devices getting assigned similar tag numbers when inserted in the same row. In practical use we often find the following:
- NFPA drawings using the metric symbols usually have 8mm tall paths.
- Common page sizes allow for 30-50 8mm rows per page.
- NFPA drawings using the inch symbols often have 1/2 inch tall paths and use large page sizes.
- Common page sizes allow for 40-50 1/2 inch rows per page.
What size page will you most likely be printing to? Back when I started out in this industry everything was sized for a plotter even if we never really printed to it. I mean a ANSI D or E sized Plan view of a project on 3-4 pages is one thing but printing a 30 page schematic for one control panel is quite another. Back in the late 90’s when large format office printers arrived, we just started to print everything to 11×17. Today I consider it the default print size for electrical drawings.
EPLAN creates all the designs in a 1:1 design space, this design space CAN be scaled to the page but I do not recommend it, just keep it simple at 1:1. For graphics or other types of drawings, use the scale tools as you desire.
The final decision on page sizes for NFPA designers is often made after careful consideration of the various issues that effect this choice. There are essentially a handful of page sizes which are used for NFPA designs which I will discuss now.
ANSI B: 11×17
Ideally you would just use this page size and be done with the discussion, however there are a few issues to consider. The symbols are getting a bit large for this page and it limits the number of circuits that you can show on a page. We are also limited to designs with about 35 page rows because of the limited page height. The design also gets VERY cramped should you decide to create pages with 2 ladders or rungs.
ANSI C: 17 x 22
I do know of EPLAN users that use this format and they are very happy with it, but they also actually still print to a plotter in full size. For me printing to 11×17 is a requirement and when I print this format to 11 x 17 it just does not look like a good fit, it leaves too much wasted space on the left and the right. However, it is a standard ANSI page size which in many shops is a must have, so give it a look, it may work for you.
ISO A2: 16.5 x 23.4
Although this is not a standard US page size, it is the page size used as an example in the NFPA 79 Annex D.
Aside from the size, it does work pretty well; it’s a good fit for rows, you can fit plenty of circuits on the page, some but not a lot of wasted space when printed to 11×17
Custom: 16.8 x26
Ok, if an ISO page size is worth consideration why not a full custom page size. We just took an ANSI D page and scaled it down to have the same aspect ratio of a 11 x 17 page. For the folks who have designs with lots of 2 ladder pages, this one has the most room for the most content.
ANSI D: 34 x 44
Works great if you are using the inch based symbol libraries but we have already discussed that. At this page size the symbols are really starting to look small especially the terminals. We can always crank up the font size for text but our hands are tied for the symbols.
Plot Frame Size Comparison
Link to: EPLAN NFPA Plotframe Size Comparison
I have provided a link to a pdf which compares the various plot frame sizes that are often considered for NFPA designs.