Note
DLP Expiry Dates: Tracking Every Installed Site Close-Out
If you close eight projects a month and each carries a twelve-month defects liability period, you could have eighty or more sites currently inside their DLP at any one time. Some signed off last week. Some expire next month. A few may have already expired with no formal close-out.
The DLP does not send reminders. The customer rarely tracks it either. When the expiry passes without a formal close-out, one of two things happens: the retention invoice stalls because neither side has confirmed the conditions are met, or the customer raises issues after the fact that are now disputed as falling inside or outside the liability period.
The DLP register is the tool that prevents both outcomes.
How Many Sites Are Currently in Active DLP?
Eight projects closed this month. Eight more the month before. After a year at that pace, roughly eighty to a hundred sites are still inside their DLP, spread across a twelve-month window at different stages.
Most contractors cannot answer how many that is without searching through contract folders. The DLP expiry date sits in the original contract, which nobody opens between handover and the retention invoice. When the invoice goes out and the customer says the DLP was never formally closed, the contractor is searching for a date they should have been tracking all along.
What Does the DLP Clock Actually Start From?
The defects liability period begins on the date the customer signs the handover document. Not the date the physical work finished. Not the date the contractor considered the job complete. The signature is the legal start.
The gap between work completion and a signed handover varies. A job physically finished in week three might get the customer’s signature in week five or six. A contractor counting from physical completion has the wrong DLP end date, sometimes by two to three weeks, which means the inspection gets scheduled at the wrong time.
Record this precisely on every project:
- Handover signature date: taken from the signed document, not a calendar estimate
- DLP term: from the contract, usually twelve months; check rather than assume
- DLP expiry date: calculated from the handover signature, not from any other reference point
For phased projects where each phase has its own signed handover, each phase starts its own DLP clock. A factory solar installation handed over in two phases produces two DLP expiry dates, not one.
Building and Maintaining the DLP Register
A DLP register is a maintained list of every installed site with three dates and two status fields:
| Field | What it holds |
|---|---|
| Site name | Client name and site address |
| Handover signature date | Date the customer signed the acceptance document |
| DLP expiry date | Handover date plus the contract term |
| Inspection scheduled | Date the close-out inspection is confirmed |
| Status | Open / Inspection done / Signed off |
The register does one job: make the answer to “which sites need a DLP inspection this month” available in seconds. Without it, that answer requires searching through contract folders.
Update the register when the handover document is signed, not when the job is physically complete. Check it at the start of each month and identify every site whose DLP expiry falls within the next 45 days. The action trigger: 30 days before the DLP expiry date, schedule the inspection and send a written notice to the customer’s site representative.
What to Send the Customer Before the DLP Closes
The 30-day notice is a short written message. It needs three things: the site name, the DLP expiry date, and a proposed inspection date. Nothing more.
A practical version:
Re: [Site Name] - Defects Liability Period Expiry Notice Our records show the defects liability period for the installation at [site name] expires on [date]. We would like to schedule a close-out inspection before that date. Please confirm a suitable time for our technician to visit with your authorized representative present.
Send it by email and keep the sent copy. If the customer does not respond within five working days, follow up by phone and note the date.
This record matters. If the customer raises defects after the DLP has formally closed, a documented attempt to conduct the inspection shifts the position considerably.
The Close-Out Document
After the inspection, the close-out document records the result. It does not need to be long. Four elements are sufficient:
- Site and installation details
- Date the inspection was conducted
- A statement that the installation was inspected and no unresolved defects under the DLP were found
- Signature and printed name of the customer’s authorized representative
This document is distinct from the inspection checklist (which records what was examined). The close-out document records that the customer’s representative confirmed the result was acceptable.
With it, the retention release invoice has a supporting document. Without it, the customer’s silence becomes ambiguous when the invoice arrives.
What the Close-Out Triggers Next
A completed DLP close-out does three things in sequence.
The retention invoice can be issued with the close-out document as supporting evidence. The customer’s representative has confirmed the installation was in good condition, so there is no new territory to contest.
Equipment warranties (manufacturer terms on panels, inverters, fixtures, and other components) continue on their own clocks. Note them in the site register alongside the DLP status, since they run to different dates from different start points.
If a maintenance agreement is not yet in place, the close-out notice is the last scheduled contact under the original contract. A site without a maintenance arrangement will call you only when something fails. If a maintenance agreement is worth proposing, this is the natural moment to raise it.
FAQ
How long does a DLP typically run on commercial electrical work in Thailand?
Twelve months is standard in most commercial and industrial contracts. Some projects specify shorter periods for specific equipment categories. The duration stated in the contract governs; check the actual contract rather than assuming twelve months applies everywhere.
What if the customer will not respond to the close-out notice?
Document your attempts: the written notice, dates of follow-up calls, and any responses. If the DLP expires with no inspection because the customer was unresponsive despite documented requests, the contractor’s position is different from one where nothing was attempted. Most customers respond once they understand the DLP close-out is also the trigger for the retention release.
Is the DLP the same as the equipment warranty?
No. The DLP covers the contractor’s liability for installation workmanship defects. Equipment warranties are manufacturer terms running on separate clocks from purchase or commissioning date. A DLP expiry does not end the equipment warranty, and vice versa. Both need tracking, but on separate registers.
The TRACE 30 program installs a site register that captures the handover signature date and calculates the DLP expiry automatically. The inspection calendar raises a job order 30 days before each expiry, without anyone having to remember to check. If you want to see how the close-out sequence works in practice, schedule a call.