(855) 355-2724
The A26-30-10 and the A50-30 are two sizes of ABB A-Line 3-pole AC contactor, and the A50 is the larger of the two. BRAH Electric’s replacement for the A26-30-10 has a catalogue rating of 28A and 20HP at 480V, with one normally open auxiliary contact. Its replacement for the A50-30-11 is listed at 54A and 40HP at 480V, with one normally open and one normally closed auxiliary contact.
A50-30 on its own is a base number. To order, you need the digits that follow it. BRAH’s 3-pole A50 listings are all A50-30-11, with or without a two-digit coil suffix. The A26-30-10 is already a complete number, and it too is listed with each coil suffix.
A26-30-10 vs A50-30 at a glance
- Both are 3-pole, 3-phase A-Line contactors rated 600V in the BRAH catalogue.
- Catalogue amperage: 28A for the A26-30-10, 54A for the A50-30-11.
- Auxiliary contacts: 1 NO on the A26-30-10, 1 NO / 1 NC on the A50-30-11.
- Both are listed with the same eight coil voltages, from 24VAC to 500/600VAC.
- They are different physical sizes. One is not a drop-in replacement for the other.
Side-by-side specifications from the BRAH catalogue
The figures below are the catalogue values of the BRAH replacement parts. Use them to compare the two sizes, then confirm against the nameplate of the contactor you have and the motor nameplate.
| Specification | A26-30-10 | A50-30-11 |
|---|---|---|
| BRAH replacement | BA26-30-10 | BA50-30-11 |
| Replaces ABB | A26-30-10 | A50-30-11 |
| Family | A-Line | A-Line |
| Main poles | 3 | 3 |
| Phase | 3-phase | 3-phase |
| Voltage | 600V | 600V |
| Amperage (catalogue) | 28A | 54A |
| Horsepower at 240V (catalogue) | 10HP | 20HP |
| Horsepower at 480V (catalogue) | 20HP | 40HP |
| Horsepower at 600V (catalogue) | 25HP | 50HP |
| Auxiliary contacts | 1 NO | 1 NO / 1 NC |
| Coil on the base listing | 120VAC | 120VAC |
| Coil voltages listed | 24VAC, 48VAC, 120VAC, 220/240VAC, 277VAC, 415/440VAC, 480VAC, 500/600VAC | 24VAC, 48VAC, 120VAC, 220/240VAC, 277VAC, 415/440VAC, 480VAC, 500/600VAC |
BRAH also lists a 4-pole A50, the BA50-40-00-84, which replaces the ABB A50-40-00-84 and has a 120VAC coil. For anything not in the table, call (855) 355-2724 with the part number.
What the differences mean in practice
Current and horsepower
The A50-30-11 is listed at nearly twice the amperage of the A26-30-10, and at twice the horsepower at each voltage in the table. Neither number in the part name is the rating: the A26 is listed at 28A and the A50 at 54A. Horsepower depends on the supply voltage, so read the row for your voltage and compare it with the motor nameplate. A contactor must be rated for at least the load it switches. Never fit the smaller size where the larger one was specified.
Auxiliary contacts
The -10 and -11 at the end of the two numbers go with the built-in auxiliary contacts. Every -30-10 listing in the A-Line catalogue has one normally open contact, and every -30-11 listing has one normally open and one normally closed. A normally open contact is the usual holding contact in a start/stop circuit. A normally closed contact is the kind used for an electrical interlock or a “stopped” signal. If your circuit needs a contact the contactor does not have built in, the catalogue lists the same add-on blocks for both sizes: the BCA5-10 (1 NO), the BCA5-01 (1 NC) and the BCAL5-11 (1 NO / 1 NC).
Physical size
The two contactors do not share a case. The catalogue gives the A26, A30 and A40 one set of overall dimensions, and gives the A50, A63 and A75 a larger set and a higher weight. Expect different mounting points and terminal sizes, and check that the larger contactor fits the space in the enclosure before you plan a change of size.
Coil
The coil is chosen separately from the size. Both sizes are listed with the same range of AC coil voltages, and in both cases the coil voltage has to equal the control circuit voltage. It does not have to equal the motor voltage.
Coil suffixes for both sizes
The two digits added to the end of the ABB number identify the coil. The same suffix means the same coil voltage on both sizes.
| Suffix | Coil voltage | A26-30-10 listing | A50-30-11 listing |
|---|---|---|---|
| None | 120VAC | BA26-30-10 | BA50-30-11 |
| -84 | 120VAC | BA26-30-10-84 | BA50-30-11-84 |
| -81 | 24VAC | BA26-30-10-81 | BA50-30-11-81 |
| -83 | 48VAC | BA26-30-10-83 | BA50-30-11-83 |
| -80 | 220/240VAC | BA26-30-10-80 | BA50-30-11-80 |
| -42 | 277VAC | BA26-30-10-42 | BA50-30-11-42 |
| -51 | 480VAC | BA26-30-10-51 | BA50-30-11-51 |
| -86 | 415/440VAC | BA26-30-10-86 | BA50-30-11-86 |
| -55 | 500/600VAC | BA26-30-10-55 | BA50-30-11-55 |
Which one do you need?
If you are replacing a failed contactor, the answer is the one that is already there. Copy the full number from the nameplate, add a B, and order that part. A starter is designed around its contactor size, and the overload relay, the conductors and the short-circuit protection were chosen to go with it.
If you are choosing a size because the motor has changed, work from the motor nameplate: voltage, full-load current and horsepower. Pick the size whose rating covers the motor at your supply voltage. The A-Line family has two sizes between these two, so the choice is not only A26 or A50.
| ABB size | BRAH base listing | Amperage (catalogue) | Horsepower at 480V (catalogue) | Auxiliary contacts |
|---|---|---|---|---|
| A26 | BA26-30-10 | 28A | 20HP | 1 NO |
| A30 | BA30-30-10 | 34A | 25HP | 1 NO |
| A40 | BA40-30-10 | 42A | 30HP | 1 NO |
| A50 | BA50-30-11 | 54A | 40HP | 1 NO / 1 NC |
Moving up a size is a design change. Have a qualified person confirm the overload relay, conductor size, protection and enclosure space, using the device markings and the applicable code. All A-Line sizes are under replacement contactors, and the guide to the ABB A26-30-10 replacement lists the smaller sizes as well.
Before you order: what to check
- The complete part number. A50-30 is not enough. Read the rest from the nameplate, for example A50-30-11-84.
- Coil voltage. Read it from the coil and match the suffix in the table above.
- Auxiliary contacts in use. Check which of the built-in contacts are wired, and whether add-on blocks are fitted.
- Number of poles. The 3-pole and 4-pole A50 are separate listings.
- Motor nameplate. Compare voltage, full-load current and horsepower with the catalogue values.
- Mounting and terminals. Compare them with the installed contactor, especially if the size is changing.
BRAH Electric is an aftermarket manufacturer, not an authorized ABB distributor. Its parts are designed in-house and tested at its facility in Carlsbad, California, and its contactors carry a 2-year warranty from the date of invoice. To have a cross-reference checked, call (855) 355-2724, Monday to Friday, 6AM to 5PM Pacific.
Safety
Either contactor is replaced with the starter de-energized. Apply lockout/tagout to the power supply and to any separate control supply, verify the absence of voltage, and leave the work to qualified personnel. The guide to wiring an A-Line contactor safely sets out the steps.
A26-30-10 and A50-30 FAQs
Can I use an A50-30 in place of an A26-30-10?
Not as a direct swap. The A50 is a larger device with a different case, so mounting and terminals will differ, and the overload relay and wiring were selected for the smaller contactor. Fit a larger size only as an engineered change. To replace a failed A26-30-10, use the BA26-30-10 with the matching coil.
Can I use an A26-30-10 in place of an A50-30?
No. The A26-30-10 has about half the catalogue rating of the A50-30-11. A contactor that is too small for the load will overheat and fail.
Is A50-30 a complete part number?
No. It names the size and the three main poles. BRAH’s 3-pole listings for this size are A50-30-11 with a 120VAC coil, and A50-30-11 followed by a two-digit coil suffix.
Do both sizes take the same auxiliary contact blocks?
The BRAH catalogue lists the BCA5-10, BCA5-01 and BCAL5-11 for both the A26 and the A50. Match the block to the ABB number on the one you are replacing.
When should I move from an A26 to a larger size?
When the motor it switches has been replaced with one whose nameplate current or horsepower is above the rating of the A26 at your voltage. Check the A30 and A40 before going to the A50.
Are the coils the same on both sizes?
The coil voltages listed are the same, and the suffix numbers mean the same voltage. The two sizes are different devices, though, so do not assume a coil taken from one will fit the other. Each contactor is listed complete with its coil.
References
- IEC 60947-4-1, Low-voltage switchgear and controlgear: contactors and motor-starters. Defines how contactor ratings and utilization categories are stated.
- NFPA 70, National Electrical Code. The installation code for motor circuits, conductors and overcurrent protection.
- OSHA 29 CFR 1910.147, The control of hazardous energy (lockout/tagout).