The short answer
Division 27 (Communications) covers structured cabling, backbone, communications pathways, audio-video and distributed communications systems such as paging, clocks and nurse call. Division 28 (Electronic Safety and Security) covers access control, video surveillance, intrusion detection, and fire detection and alarm. A complete specification names the standard and edition for each system, a basis of design product, testing and certification requirements and the closeout deliverables, and it assigns pathways and firestopping to one division so nothing falls between trades.
| Division 27 | Communications (CSI MasterFormat) |
|---|---|
| Division 28 | Electronic Safety and Security |
| Cabling standards | ANSI/TIA-568.2-E copper, TIA-568.3-D fiber |
| Labeling | ANSI/TIA-606-C administration standard |
| Camera procurement | NDAA Section 889, 2 CFR 200.216 on federal funds |
| Pathways and firestop | TIA-569, assign firestopping to one division |
What Division 27 and Division 28 contain in MasterFormat#
CSI MasterFormat is the numbering system that organizes a construction specification, and since the 2004 edition it has separated low voltage work from electrical. Division 26 is Electrical. Division 27 is Communications: structured cabling, network equipment, voice, audio-video and distributed communications systems such as paging, clocks and nurse call. Division 28 is Electronic Safety and Security: access control, video surveillance, intrusion detection, and life safety systems including fire detection and alarm.
The split has a practical purpose. It lets the owner bid the communications and security work to a low voltage specialist while the electrical contractor bids Division 26, and it gives each contractor a document that describes its own scope. It only works if the specifier draws the lines deliberately. A Division 27 section that assumes Division 26 will provide conduit, and a Division 26 section that assumes the reverse, produces a pathway nobody priced.
Telelink Business Services is a licensed C-7 Low Voltage Systems Contractor, CSLB License #472017. We bid Division 27 and 28 scopes across California, and the sections below are the ones we most often see on commercial, institutional and multifamily projects, and most often see missing.
The sections a commercial low voltage spec should include#
The table lists the MasterFormat section numbers that cover a typical commercial project. Not every project needs every section, but every system on the drawings should have a home in one of them.
| Section | Title | Use it for |
|---|---|---|
| 27 05 00 | Common Work Results for Communications | General requirements, coordination, submittal and closeout rules for all of Division 27 |
| 27 05 26 | Grounding and Bonding for Communications Systems | Telecom bonding backbone, busbars, rack bonding per TIA-607 |
| 27 05 28 | Pathways for Communications Systems | Conduit, sleeves, tray, J-hooks, surface raceway, firestopping assignment |
| 27 05 53 | Identification for Communications Systems | Labeling scheme per TIA-606, label materials, record drawings |
| 27 10 00 | Structured Cabling | Umbrella section when backbone and horizontal are combined |
| 27 11 00 | Communications Equipment Room Fittings | Racks, cabinets, ladder rack, patch panels, backboards, room finishes |
| 27 13 00 | Communications Backbone Cabling | Fiber and copper riser between MDF and IDFs, building entrance |
| 27 15 00 | Communications Horizontal Cabling | Cat6 and Cat6A drops, outlets, patch cords, wireless access point drops |
| 27 21 00 | Data Communications Network Equipment | Switches, routers, wireless access points, firewalls when in the contract |
| 27 41 00 | Audio-Video Systems | Conference rooms, classrooms, displays, control systems |
| 27 51 00 | Distributed Audio-Video Communications Systems | Paging, background music, mass notification audio, CATV distribution |
| 27 52 23 | Nurse Call and Code Blue Systems | Nurse call and emergency call in healthcare and senior housing |
| 28 05 00 | Common Work Results for Electronic Safety and Security | General requirements for all of Division 28 |
| 28 10 00 | Access Control | Controllers, readers, credentials, door devices, software, integration |
| 28 20 00 | Video Surveillance | Cameras, recording, video management, storage, retention |
| 28 30 00 | Security Detection, Alarm, and Monitoring | Intrusion detection; BSIS licensed alarm company scope in California |
| 28 46 00 | Fire Detection and Alarm | Fire alarm contractor scope, outside C-7 |
Two systems deserve a note. Intercom and telephone entry do not have a single obvious section; most specifiers put video intercom under 28 10 00 as part of access control and put SIP intercoms tied to the phone system under 27 51 00. Wireless access points are usually specified in 27 21 00 with their cabling in 27 15 00; the specification should say who mounts and who configures.
What to require in every section#
A section that names a system but not a standard leaves the contractor to decide what “complete and working” means. Each section should contain the same six elements.
Standards: name the edition. For cabling that is ANSI/TIA-568.2-E for balanced twisted pair, TIA-568.3-D for optical fiber, TIA-569 for pathways and spaces, TIA-606 for administration, TIA-607 for bonding and grounding, and the California Electrical Code (Title 24, Part 3) Articles 725, 770, 800, 805 and 820 as applicable. The 2025 CEC is based on the 2023 NEC, which created Article 722 for power-limited cables and reorganized what remains in Article 725, so cite article and section numbers from the edition the project is permitted under rather than copying them from an older specification. For access control name UL 294. For nurse call in licensed healthcare name UL 1069. For cameras on federally funded work name NDAA FY2019 Section 889 and 2 CFR 200.216.
Products: a basis of design with model numbers, and a substitution procedure. State whether the cabling system must be a single manufacturer’s end-to-end channel to qualify for an extended warranty. State the cable jacket rating by location (CMP plenum, CMR riser) rather than leaving it to the mechanical drawings.
Submittals: product data, shop drawings showing rack elevations and pathway routing, a labeling scheme for approval before any label is printed, a test plan, and for cameras a manufacturer-of-record statement.
Testing: which test, on what, with what tester, and who witnesses. For copper, permanent link or channel certification to the named category with a field tester rated for it, Level III for Cat6 and Level IIIe for Cat6A per ANSI/TIA-1152-A. For fiber, Tier 1 loss testing at minimum, with Tier 2 OTDR traces where the owner wants them. For access control and cameras, a point-by-point functional test with a checklist the owner signs.
Labeling: reference 27 05 53 and require that every cable, outlet, patch panel port, rack and pathway carry a unique identifier per TIA-606 that matches the record drawings.
Warranty and closeout: the installation warranty term, any manufacturer system warranty, test results in native tester format and PDF, as-built drawings in the owner’s CAD or PDF format, and the administrative records (IP addresses, credentials, VLANs, license keys) that the owner’s IT staff will need on day one. Our MDF and IDF buildout guide describes what a complete closeout looks like for a network room.
Drawing the line with Division 26 and Division 08#
Most change orders on low voltage scopes trace back to two boundaries. The first is power and bonding. Dedicated circuits, receptacles at racks, and the bonding conductor from the telecom busbar to the building electrical service ground are electrical scope under a C-10 license. The Division 27 section should say so and require the communications contractor to show those handoff points on its shop drawings. The Division 26 section should list the telecom rooms and circuit count so the electrician prices them.
The second is the door. Access control readers, controllers, power supplies, door position switches, request-to-exit devices and cabling are Division 28. Electrified strikes, maglocks, panic hardware, closers and automatic operators are Division 08 door hardware, furnished by the hardware supplier and installed by the door hardware installer or a C-28 Lock and Security Equipment contractor. A 28 10 00 section that says “provide a complete access control system” without a hardware schedule cross-referenced to Division 08 invites both contractors to exclude the strike. The fix is a door-by-door matrix in the specification or on the drawings that lists every device at each opening and the section that furnishes it.
The California C-7 license guide covers the licensing side of these boundaries.
Gaps that turn into change orders#
These omissions come up repeatedly in the specifications we price. Each has a short fix.
Pathway scope not assigned. Neither 26 05 33 nor 27 05 28 says who provides the sleeves, tray and J-hooks. Fix: put it in 27 05 28 and reference that section from Division 26.
No labeling scheme. The spec says “label per TIA-606” but does not say whether the owner has an existing scheme, whether room numbers follow the architectural or the facilities numbering, or who approves the scheme. Fix: require a labeling scheme submittal and name the approving party.
No firestopping assignment. Cables pass through rated walls and floors and nobody is named to seal them. Fix: assign firestopping of communications penetrations to Division 27 (or to Division 07 84 00 with a coordination note), and require listed systems.
No line between Division 26 and 27 on bonding. Fix: state that Division 26 provides the bonding conductor to the busbar and Division 27 provides the busbar, the backbone and rack bonding per TIA-607.
No NDAA language on cameras. Fix: add the Section 889 and 2 CFR 200.216 requirement, the manufacturer-of-record submittal, and the right to reject rebadged product. Our NDAA camera compliance guide has sample language.
Door hardware split between 08 and 28 without a matrix. Fix: a door hardware and security matrix on the drawings.
No cable count. The drawings show outlets but no drop count per outlet and no spare requirement. Fix: state drops per outlet type and a spare percentage at each IDF.
No owner-furnished equipment list. Switches, wireless controllers and cameras the owner buys directly are not identified, so bidders include or exclude them silently. Fix: an OFCI schedule.
No wireless survey requirement. Access points are placed on plan without a predictive or on-site survey. Fix: require a survey submittal before rough-in.
Pre-bid review checklist for a Division 27 and 28 section#
Use this table when reviewing a Division 27 and 28 specification before it goes out to bid.
| Item | Where | Check |
|---|---|---|
| Standards named with edition | Every section | TIA-568.2-E, 568.3-D, 569, 606, 607; CEC 725, 770, 800, 805, 820; UL 294; UL 1069 where applicable |
| Cable ratings by location | 27 13 00, 27 15 00 | CMP in plenum, CMR in riser, OSP where required |
| Pathway scope assigned | 27 05 28 | Sleeves, tray, J-hooks, surface raceway, and who firestops |
| Power and bonding handoff | 27 05 26, Division 26 | Circuits and bonding conductor in 26; busbar and backbone in 27 |
| Labeling scheme | 27 05 53 | Scheme submittal, approving party, label materials |
| Testing method | 27 13 00, 27 15 00, 28 10 00, 28 20 00 | Certification tester level, fiber tier, functional test checklist |
| Submittals | Every section | Product data, shop drawings, labeling scheme, test plan, manufacturer of record |
| NDAA compliance | 28 20 00 | Section 889, 2 CFR 200.216, right to reject rebadged product |
| Door hardware matrix | 28 10 00, Division 08 | Every device at every opening assigned to a section |
| Intrusion and monitoring | 28 30 00 | Assigned to a BSIS licensed alarm company, not bundled into C-7 scope |
| Fire alarm interface | 28 46 00 | Fire alarm contractor scope; any door release interface defined |
| Owner-furnished equipment | 27 21 00, 28 20 00 | OFCI schedule with who receives, stores and configures |
| Drop counts and spares | 27 15 00 | Drops per outlet type, spare percentage per IDF |
| Wireless survey | 27 21 00 | Predictive or on-site survey submittal before rough-in |
| Warranty | Every section | Installation term plus any manufacturer system warranty by name |
| Closeout | 27 05 00, 28 05 00 | Test results, as-builts, admin records, training |
| Occupied building provisions | 27 05 00, 28 05 00 | Phasing, notice, cutover sequence if the building is in use |
For an occupied renovation, the last row matters as much as any of the others; our occupied building guide explains what the specification should say about phasing and cutover.
Next step#
If you are writing or reviewing a Division 27 or 28 specification for a California project, send us the draft and we will mark the gaps that would show up as RFIs or change orders. Request a bid or reach us through the for general contractors page, and we can return comments in the same format as this checklist.
This article is general information for planning and specification, not a bid, engineering advice or legal advice. Codes and standards change; confirm the current edition with the authority having jurisdiction. Scope and price for a specific building come only in a written proposal.