PoE standards and the cabling they need.
PoE (15W), PoE+ (30W), PoE++ Type 3 (60W), PoE++ Type 4 (90W) deliver progressively more power through ethernet cables. Cable choice affects what PoE class is supported.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
PoE classes: 802.3af (PoE, 15.4W), 802.3at (PoE+, 30W), 802.3bt Type 3 (PoE++, 60W), 802.3bt Type 4 (PoE++, 90W). Power increases come with higher conductor heating, requiring careful cable selection: Cat5e/Cat6 acceptable for PoE/PoE+, Cat6a 23 AWG strongly recommended for PoE++ at full distance, careful cable bundling for high-PoE density. Modern Wi-Fi 6E/7 APs, motorized cameras, and some monitors require PoE++; cabling must support it.
01How PoE drives cable selection.
Power over Ethernet sends DC power along with data through the same twisted-pair conductors. Higher PoE wattage means higher current flow, which heats the conductors. Standard Cat5e/Cat6 24 AWG conductors handle PoE+ (30W) fine but can experience meaningful heating at PoE++ (60-90W) levels, particularly when many PoE++ cables bundle together. Heating affects reliability, can degrade insulation over time, and in extreme cases reduces effective transmission distance.
Cat6a 23 AWG construction has thicker conductors (23 vs 24 AWG) that handle PoE++ heating better. For installations where most or all cables carry PoE++ (high-AP-density buildings, PoE++ powered monitor deployments), 23 AWG Cat6a is the appropriate spec. For mixed installations with some PoE+ and PoE++, 24 AWG Cat6a still works if cable bundling stays moderate.
02Three deployment scenarios.
Low PoE density — PoE/PoE+ on most
Standard office with phones, occasional APs, security cameras. Cat6 or Cat6a 24 AWG works fine. PoE++ on a handful of cables doesn't drive cable selection.
Mixed PoE — high-density APs plus standard
Modern office with Wi-Fi 6E/7 AP density plus standard phones/printers. Cat6a 24 AWG works for most installs; consider 23 AWG if AP density is high (1 per 750 sq ft or denser) or PoE++ deployment is extensive.
High PoE density — PoE++ on majority
Heavy PoE deployment (PoE-powered monitors, many APs, motorized cameras throughout). Cat6a 23 AWG appropriate, cable bundling limits enforced (typically <25 cables per bundle for high-PoE), thermal calculations during design.
03Practical guidance for Marin business.
For most Marin business structured cabling: Cat6a 24 AWG is sufficient. PoE deployment in typical commercial isn't extreme enough to require 23 AWG. Cost premium for 23 AWG over 24 AWG is 10-20%; worth the upgrade for known high-PoE deployments or future-proofing 15+ year cable life. We default to 24 AWG and recommend 23 AWG upgrade when specific deployment justifies it.
Cable bundling matters more than conductor gauge in many real-world scenarios. Marin TI projects sometimes bundle 50+ cables in tight pathways; that bundling creates more PoE thermal issues than conductor gauge selection. Best practice: limit bundles to 25 cables in high-PoE installations, use cable tray with airflow rather than tight conduit bundles, design pathway with thermal management in mind. We follow TIA cable management guidelines in installations.
Common questions.
Will PoE++ damage my Cat5e cabling?
Probably not in moderate use, but Cat5e isn't ideal for PoE++. Cat5e 24 AWG can handle PoE++ at modest densities but lacks the headroom Cat6a provides for sustained high-power deployments. For installations needing PoE++, upgrade to Cat6a if scope allows. Existing Cat5e cabling with occasional PoE++ devices typically continues working without damage but with reduced margin.
What temperature rise should I expect with PoE++?
Modest in well-designed installations. Single PoE++ cable rises 5-15°C above ambient under full load. Cable bundle of 25-50 PoE++ cables can rise 20-30°C in tight pathway. Cable tray with airflow keeps rise lower than conduit bundles. Manufacturer specifications include PoE thermal derating tables; we follow them in design.
Do I need PoE switches for PoE devices?
Yes — PoE devices need PoE-capable switches that inject power into the ethernet cable. PoE+ switches handle PoE/PoE+ devices; PoE++ switches handle the full standard range. Network equipment scope is separate from cabling scope but coordinates during install — we work with tenant's IT consultant or directly with switch deployment for end-to-end functionality.
Will PoE++ affect cable distance limits?
Minimally for properly-specified cabling. PoE++ at 90W per port to 100m runs in Cat6a 23 AWG works to standard. For 24 AWG Cat6a at full PoE++ to 100m, manufacturers sometimes derate slightly. Practical effect: stay within 90m for high-PoE deployments to have headroom; use 23 AWG if pushing to 100m at full PoE++. For typical commercial runs under 60-80m, no derating concerns.
How do you handle pricing — flat fee or hourly?
Both, depending on scope. Routine service calls and predictable scope (panel replacement, EV charger install, transfer switch install, fixture replacement) are flat-fee quoted up front. Diagnostic visits and emergency scope are hourly because we don't know what we'll find. Either way, you get a written quote before work starts on anything significant, and we don't proceed beyond the quote without your sign-off.
How quickly can you schedule?
Depends on scope and season. Emergency dispatch: same-day across Marin County (1-3 hours business hours, 1-4 hours after-hours). Same-day standard service: 3-6 hours from call when capacity allows; otherwise next business day. Scheduled service work: 1-3 weeks typical. Larger projects requiring permits and PG&E coordination: 4-12 weeks depending on scope. We're upfront about timeline at the quote stage.
What warranty do you offer on work?
Our standard residential warranty: 2 years on labor, manufacturer warranty on parts (varies by product — typically 1-10 years). Major installs (panels, generators, EV chargers) often have longer manufacturer warranties (5-10 years). If there's an issue with our work in the warranty period, we come back and fix it at no cost. We also stand behind work past warranty — repeat customers and referrals matter more than a transactional fix.
Are you licensed and insured?
Yes. California State License Board C-10 Electrical Contractor #989290, in good standing. Carry general liability insurance and workers' compensation insurance as required by California law. Bondable on projects requiring it. Happy to provide proof of insurance to clients or property managers on request. License lookup: cslb.ca.gov.
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