What Is a Relay Jumper Bar? Types and Selection Criteria
A relay jumper bar is a comb-shaped part fitted on top of relay sockets lined up on a DIN rail to link their same-function terminals.
A relay jumper bar (relay bridge) is a comb-shaped connecting part that is fitted on top to link the same-function terminals of relay sockets lined up side by side on a DIN rail. It is used to feed the coil common or contact common of many slim PLC relays without running wires one by one; it reduces wiring time and wire clutter inside the panel.
Types of relay jumper bars
| Type | Where it is used | Product in the catalogue |
|---|---|---|
| 20-way jumper bar | Long relay rows; common terminal for up to 20 sockets | Isıso IRK20 (black, blue, red), Molwex SUK 02 (170 139) |
| 8-way jumper bar | Short relay groups | Molwex 060 210, for MS-S1CO and MS-S2CO sockets |
Coloured jumper bars make it easier to tell different potentials apart in the same panel at a glance (for example the plus and minus supply, or two separate control circuits). Set the colour scheme according to your panel project's conductor colour rules.
Selection criteria
- Socket series and pitch: The teeth of the jumper bar are spaced for a specific socket width. According to its product name, Molwex 060 210 is for MS-S1CO and MS-S2CO sockets; confirm which socket series the Isıso IRK20 and Molwex SUK 02 fit on the product page or in the manufacturer's datasheet.
- Number of poles: The jumper bar must have as many teeth as there are relays in the row. For groups longer than 20 relays, split the row and feed each section separately.
- Terminal to bridge: Either the coil common (for example all A2 terminals) or the contact common (11 / COM) is bridged. Relays whose common terminal must be at a different potential are not put on the same jumper bar.
- Total current: The jumper bar carries the current of all loads from the feed point to the furthest relay. Check the jumper bar's rated current in the manufacturer's data; if the total current is high, feed the row from the middle or split it.
Common mistakes
- Using a terminal block jumper: Terminal block top jumpers are made to the pitch of DIN rail terminal blocks; the Onka terminal jumpers in the catalog do not fit the jumper slot of the Isıso and Molwex relay sockets.
- Connecting different coil voltages to the same jumper bar: If relays with 24 V DC and 230 V AC coils are in the same row, the jumper bar joins the two circuits. Use a separate row or a separate jumper bar for each voltage.
- Tightening the terminal before the jumper bar is fully seated: Contact between the tooth and the terminal stays poor and the connection heats up.
Relay jumper bars in the catalogue
The Relay Jumper Bars category has 5 active products, all sold by the piece:
- Isıso (3): IRK20-BLACK, IRK20-BLUE and IRK20-RED; 20-way, black, blue and red.
- Molwex (2): SUK 02 top jumper 20-way (170 139) and 8-way jumper (060 210).
The sockets the jumper bars fit on are in the Relay Sockets category, and slim relays sold with their socket are in PLC PCB Relays.
Frequently asked questions
What does a relay jumper bar do?
It joins the same terminals of relay sockets lined up side by side with a single part. For example, it connects the A2 terminal of 16 relays to the common minus without running a wire to each one.
Can a terminal block jumper be used on a relay socket?
Not for the products in the catalog. The tooth spacing of a terminal block jumper follows the width of the DIN rail terminal block, while that of a relay jumper bar follows the socket width. Some manufacturers' slim relay systems share jumpers; check this in the manufacturer's datasheet.
Does it fit another brand's relay socket?
Tooth spacing and tooth shape vary by manufacturer. Unless the manufacturer states compatibility, choose the jumper bar from the same brand as the socket and with a code that matches the socket series.
What do the jumper bar colours mean?
The colour does not change the jumper bar's electrical properties; it only shows which jumper bar carries which potential.