Generator Interlock Kit for Siemens Panels
Siemens makes its own generator interlock kits, the ECSBPK series, and the right one depends on which breakers your panel takes and how the main breaker sits next to the generator breaker. For the newer Ultimate and Rock Solid load centers, the choice comes down to the main breaker's amp rating.
Find the kit for your panel
Read the panel first
Open the door and find the label. Write down:
- The load center catalog number and whether it says Ultimate or Rock Solid.
- The main breaker type and amp rating, printed on the main breaker itself.
- Whether the main sits at the top of the panel or down in the branch spaces.
- Whether the panel is indoor or an outdoor meter-main combination.
Take a photo of the label and the breakers together. Every kit maker asks for one.
Siemens ECSBPK kits
These come from the load center section of the Siemens SPEEDFAX catalog. QP, QPH and HQPH are Siemens' standard plug-in breakers.
| Kit | Fits | Breakers it interlocks |
|---|---|---|
| ECSBPK01 | Load centers or meter combos that take two-pole breakers opposite each other | QP, QPH, HQPH |
| ECSBPK02 | Load centers or meter combos with a two- or four-pole breaker beside a two-pole breaker | QP, QPH, HQPH |
| ECSBPK03 | Ultimate and Rock Solid load centers, 150 A and up | MBK150A, MBK200A or MBK225A main to a QP-type breaker |
| ECSBPK04 | Ultimate and Rock Solid load centers, 125 A and below | MBK100A or MBK125A main to a QP-type breaker |
| ECSBPK05 | Equipment with a QNR frame main beside a two-pole breaker | QNR, QNRH, HQNR with QP types |
| ECSBPK06 | Equipment with a QN frame main beside a two-pole breaker | QN, QNH, HQN with QP types |
| ECSBPK07 | Two QNR or two QN breakers side by side | QNR or QN families |
| ECSBPK08 | 8-space over/under meter combinations, limited models | QPP, QPPH with QP types |
| ECSBPK09 | 20-space over/under meter combinations, limited models | QPP, QPPH with QP types |
Two details from the catalog that trip people up. The kits attach to the breakers, not the panel cover. And each kit takes up the two spaces next to the two-pole breaker it locks, and those spaces can't take filler plates. So plan on losing a couple of branch spaces.
Ultimate and Rock Solid panels: ECSBPK03 or ECSBPK04
If your panel is an Ultimate or Rock Solid load center with an MBK main at the top, read the amp rating on the main. A 150, 200 or 225 amp MBK main takes the ECSBPK03, and a 100 or 125 amp MBK main takes the ECSBPK04.
Older Siemens, ITE and Murray panels
GenInterlock says Murray panels often share layouts with some Siemens and ITE panels. GenInterlock lists aftermarket kits for Siemens panels made before and after March 2020 as separate products, plus vertical-throw mains, left-column mains and outdoor meter mains. Several of its Siemens kits are also listed for Murray, ITE or Gould panels. If the ECSBPK chart doesn't match your panel, that's the next place to look, or see our Murray interlock kit page.
Buy a kit that's listed by a testing lab. Interlock Technologies says its kits are MET listed to UL standards, and an inspector will look for a listed product installed to its instructions.
Besides the kit
You'll need a two-pole QP-family back-fed breaker sized for the generator, an outdoor inlet box and a matching cord. Interlock Technologies suggests a 30 amp back-feed breaker for generators up to 8,000 watts and a 50 amp setup above that.
FAQ
What is an electrical panel interlock kit?
It's a metal plate or slide that mounts between the main breaker and a generator breaker so only one can be on at a time. That stops generator power from flowing out to the utility lines. Siemens calls its versions manual transfer interlock kits.
Can I use a Siemens circuit breaker in a GE panel?
Only if the breaker is listed or classified for that panel, which the panel label will say. A breaker that fits the bus isn't the same as one that's approved for it. For the generator breaker, Interlock Technologies says the breaker style must match the panel.
Are Siemens and Square D breakers interchangeable?
No. Square D QO and Homeline breakers are built for Square D panels, and Siemens QP breakers are built for Siemens panels. Use the brand and type printed on your panel label, including for the back-fed generator breaker.
How do I install a generator interlock kit?
An electrician turns off the main, removes the cover, installs the back-fed breaker in the position the kit calls for, and mounts the plate per the kit instructions. Then they run wire to the outdoor inlet and label everything. It's live-panel work that usually needs a permit, so it's not a good first electrical job.
Sources
- Siemens Industry, Inc.SPEEDFAX 2017 Product Catalog, Section 1: Load Centers and Circuit Breakers, Manual Transfer Interlock Kits (p. 1-26) (opens in a new tab)
- GenInterlockSiemens generator interlock kits (opens in a new tab)
- Interlock TechnologiesInterlock kit FAQs (opens in a new tab)
- GenInterlockMurray generator interlock kits (opens in a new tab)