When you sub under a general contractor, its contract will demand additional-insured status on your general liability — and for an electrical contractor that usually takes two endorsements, not one. CG 20 10 adds the general contractor for your ongoing operations while your crew is on the job; CG 20 37 extends that status to your completed operations after the power is on and the work is signed off. The second one is the piece that gets missed.
The short version: additional-insured status is added by a real endorsement to your general liability, not by the certificate that proves it exists. In ISO’s system the two that matter are CG 20 10 for your ongoing operations while your crew is on the job and CG 20 37 for your completed operations after the electrical is energized and signed off — and for a trade whose completed-operations tail is a fire in the panel or connection it leaves behind, the completed-operations one is the piece that gets missed. The general liability page owns the coverage architecture; this post is about the contract document that demands it and how the two endorsements answer it.
Certificate-of-insurance season: what the contract is actually demanding
The requirement is almost never a handshake. It is a clause in a subcontract, a master services agreement, or a purchase order, and it comes paired with a demand for a certificate of insurance evidencing it. What an electrical contractor has to understand is that the clause is asking for two related but different things: a real endorsement on the policy that grants additional-insured status, and a certificate that proves the endorsement exists.
The endorsement is the coverage. The certificate is only the evidence. A general contractor who collects a certificate and files it has proof that coverage was represented on a given day — not the coverage itself. The status that actually lets your policy respond on the GC’s behalf lives on the endorsement attached to your policy, which is why the honest first move is always to read what is on your declarations page rather than trust that a certificate settles the question.
CG 20 10 versus CG 20 37: the ongoing / completed-operations split
When a contract asks you to add a general contractor as an additional insured, the coverage is granted by a specific endorsement attached over the standard commercial general liability form — typically the occurrence version known as CG 00 01. In ISO’s system the two endorsements that matter for an electrical sub are:
- CG 20 10 — ongoing operations. Adds the general contractor as an additional insured for your ongoing operations, the protection it wants while your crew is on the job and the wiring is in progress.
- CG 20 37 — completed operations. Extends that additional-insured status to your completed operations, the protection the GC wants after the power is on, the job is signed off, and your crew has left.
They are not interchangeable, and they are not a matched set you automatically get together. Older additional-insured forms once folded both windows into a single endorsement; ISO’s modern forms split them apart, so completed-operations status now comes from its own endorsement rather than riding along with the ongoing-operations one. A policy can carry one without the other, which means a general contractor can hold an endorsement that covers it for the wrong window entirely. Editions and exact form language vary by carrier, so the form number written into a contract is a starting point to confirm against your policy, not proof of what is actually attached.
Why the completed-operations endorsement is the one electrical subs miss
The reason the pair matters comes straight from the nature of electrical work, and it is why a general contractor that has been burned once asks an electrician for the completed-operations endorsement specifically. Ongoing-operations status protects the general contractor while your crew is on the job, but it can leave the GC without additional-insured status once you have wrapped up and gone — and the completed-operations tail is precisely when the worst electrical claim tends to surface. A panel, connection, splice, or circuit you install or service keeps energizing after final payment: it carries load, heats and cools, and works behind a finished wall long after the crew is gone. A loose termination that overheats months after the job, an overloaded circuit that finally ignites, or a bad splice in a junction box that arcs and starts a fire in a building that is not yours is the classic completed-operations claim — and it usually shows up long after the crew has left the site. For an electrician who runs fire-alarm or life-safety wiring, the same tail includes a life-safety circuit that fails to do its job when a real fire finally tests it.
That is the gap the completed-operations endorsement closes. It extends additional-insured status to your completed operations, so the general contractor is still protected for liability connected to your finished electrical work after your crew is gone. Requiring only the ongoing-operations endorsement protects the GC during the weeks you are on the job and leaves it exposed during the months and years afterward — which is backwards for a trade whose signature exposure is the fire in the work it leaves behind. This is the same completed-operations exposure the general liability policy is built around; the additional-insured endorsement simply extends that one piece to the GC, and only if the completed-operations endorsement is actually on the policy. The panel that ignites two months after final inspection is not just your problem — it is the general contractor’s nightmare too, which is exactly why a careful GC wants its additional-insured status to reach that far.
Real-World Scenario: An electrical sub wires a commercial tenant build-out and sets the panel under a general contractor, passes final inspection, energizes the system, and demobilizes. Months later a connection in that panel overheats behind a finished wall and starts a fire that damages the space and the tenant’s equipment; the property-damage claim names both the electrician and the general contractor. Because the electrician’s policy carried the completed-operations additional-insured endorsement the contract required, the general contractor had the status it bargained for on the finished electrical work — not just for the weeks the crew was on site. Had the electrician added only the ongoing-operations endorsement, the GC’s additional-insured status would have run out the day the crew drove away, right before the fire exposure it cared about actually surfaced.
Blanket versus scheduled additional insured
There are two ways a policy grants additional-insured status, and the difference is practical. Scheduled coverage lists each party by name on the endorsement — every general contractor added one at a time. Blanket coverage grants the status automatically to any party you have agreed in a written contract to add, without naming each one.
For an electrical contractor bidding job after job, blanket wording is usually far more workable than scheduling every general contractor separately, because certificate requests arrive constantly and scheduling each one by hand is slow and easy to miss. But whether your policy actually carries blanket wording — and whether that blanket wording reaches completed operations, not just ongoing operations — depends on the endorsements attached to your specific policy. Terms and forms vary by carrier, so this is another place to read rather than assume the coverage is broad. The commercial and industrial electrical work where general contractors, additional-insured demands, and higher limits concentrate is exactly where this wording earns its keep.
Wrap-ups: when the additional-insured question changes
On some larger commercial and public projects the owner or general contractor provides the liability coverage for everyone on the job through a wrap-up — an owner-controlled or contractor-controlled insurance program that enrolls the subs under one policy. On a wrap-up job the additional-insured conversation shifts, because the GC’s own program is meant to respond, and your own general liability may be carved back for the enrolled work. It does not make your coverage irrelevant: wrap-ups have eligibility rules, exclusions, and off-site or non-enrolled work that still runs on your own policy, and you still carry your completed-operations fire exposure on everything the wrap-up does not cover. The honest instruction is the same — read what the specific project documents require against what your own policy actually carries, rather than assume the wrap-up handles all of it.
What additional-insured status does not do
Additional-insured status is about who else your general liability protects — not about widening what general liability covers for you, and not about handing anyone a separate bucket of coverage. The claims an additional insured brings share your limits, which is one reason an electrical contractor watches how many additional-insured requirements are stacking against a single set of limits, and why contracts that demand both higher limits and additional-insured status often push a sub toward an umbrella over the primary policy.
It also does not reach your own people or property. Injuries to your own crew — an electrocution, an arc-flash burn, or a fall, the signature electrical injuries — run through workers compensation, a separate line. Your vehicles and bucket trucks run through commercial auto, and your testers, meters, benders, wire spools, and staged fixtures through contractors equipment. Additional-insured endorsements add a general contractor to your general liability for liability connected to your work; they do not turn general liability into a policy that also answers your crew or your trucks.
Read the contract against your endorsements before the certificate request
The takeaway is straightforward: for an electrical contractor working under general contractors, additional-insured status usually takes two endorsements — one for ongoing operations while you energize the job, one for completed operations after you leave — and the completed-operations piece is the one that gets missed on a policy bought on price. Confirm both are attached, check whether your status is blanket or scheduled, and read a general contractor’s insurance requirements against your own endorsements before you sign, not when a certificate request lands mid-job. Coverage depends on the specific policy and the endorsements actually attached, so it is worth reading rather than assuming. When you are ready, start a quote and send us the contracts you are bidding, read the full general liability page to see how the completed-operations coverage the endorsement extends actually works, or browse the coverage overview to see where each line sits.