Which SIPROTEC 5 device do you actually need?
Short answer. Within one SIPROTEC 5 device type, the order number (material number, e.g. P1B163530) does not change the protection function — it changes the hardware build: how many binary inputs and outputs the device carries, how much panel or rack width it occupies, and whether it has a large or small local display. The device type code (7SD87, 7SD86, 7SA86 …) carries the function; the material number carries the equipment. Replacement is only interchangeable when both match.
What actually differs between two order numbers of the same device type
Read directly from our own catalogue entries for eight SIPROTEC 5 line differential protection devices. All eight are new-original Siemens units; none of them is a different protection function.
| Siemens material no. | Device type | Binary inputs (BE) | Binary outputs (BA) | Housing width | Local display |
|---|---|---|---|---|---|
| P1B163530 | 7SD87 | 27 | 36 (22ST + 14F) | 2/3 × 19 in | Small |
| P1B219200 | 7SD87 | 11 | 9 (3ST + 6F) | 1/3 × 19 in | Small |
| P1B298605 | 7SD87 | 91 | 25 (19ST + 6F) | 1 × 19 in + 1/3 × 19 in | — |
| P1B389129 | 7SD87 | 31 | 38 (30ST + 8F) | 1/2 × 19 in | Small |
| P1B100009 | 7SD86 | 27 | 17 (11ST + 6F) | 1/2 × 19 in | Large |
| P1B172866 | 7SD86 | 23 | 22 (14ST + 8F) | 1/2 × 19 in | Large |
| P1B229746 | 7SD86 | 19 | 30 (22ST + 8F) | 1/2 × 19 in | Small |
| P1B305228 | 7SD86 | 27 | 17 (11ST + 6F) | 1/2 × 19 in | Large |
Three practical consequences when you are replacing a device or specifying a spare
Binary inputs and outputs set the wiring scope.
A device listed with 91 BE and 25 BA cannot be swapped for one with 11 BE and 9 BA without dropping signals; the same is true in reverse, where unused inputs simply stay unconnected. Count what your existing cubicle actually terminates, then match the number.
Housing width sets the panel cutout.
The 19-inch figures are the space the housing needs. 1/3 × 19 in and 2/3 × 19 in are half- and third-width cases; 1 × 19 in + 1/3 × 19 in is a two-part housing that needs one full width plus a third. A wider replacement means reworking the panel, not just re-screwing the device.
Display size is a local-operation choice.
Large-display variants are for panels where staff read events and operate the device on the unit itself; small-display variants assume operation through the station bus and a control centre.
What the catalogue cannot tell you
Whether a given device type is the right protection function for your network — that depends on your CT/VT dimensioning, neutral earthing and the settings manual. We publish the manufacturer order code and the measured technical data of each unit, and we deliberately do not extrapolate beyond them. For function selection, Siemens’ own SIPROTEC 5 manual is the authority; for everything about the physical unit — order code, I/O count, housing, condition, delivery — ask us.
Ordering without a material number
Send the nameplate text of the device you are replacing (device type plus the seven- or eight-digit material number) through the enquiry form. If the exact variant is no longer buildable, we quote the closest orderable device and state which attributes differ, so you can check the panel cutout and the I/O count before you commit.
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