Overview

Belden 88770 is a CMP plenum-rated multi-conductor cable: three 18 AWG (19×30) tinned copper strands with FEP insulation and FEP jacket, an overall Beldfoil® shield (100% coverage), and a 20 AWG drain. Key specs include 300 V rating, −70 °C to +200 °C operating range, and conductor colors black/white/red. The closest non-plenum equivalent is Belden 8770 (PE/PVC, CM).[1][2][6][7]

Scientific Validity

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Headline electrical figures: conductor DCR 6.4 Ω/1000 ft; capacitance 54 pF/ft (conductor–conductor) and 96 pF/ft (to shield).[6] A 10 m (≈33 ft) run totals ≈1.78 nF; with a 1 kΩ source, the RC cutoff is ≈89 kHz (≈890 kHz at 100 Ω), i.e., well above the audible band. Thus audible impact for typical home line-level lengths is expected to be minimal. We found no independent measurements demonstrating audible superiority of 88770 over other shielded 3-conductor cables.[1][6][7]

Technology Level

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The construction—3×18 AWG stranded with Beldfoil® + drain and FEP dielectric/jacket—is a mature industrial recipe. It offers environmental robustness (wide temperature, plenum rating) rather than audio-specific innovations or measurable performance advantages in typical listening scenarios.[1][6]

Cost-Performance

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Representative market price is 5.22 USD/ft.[3] A functionally and electrically equivalent-or-better alternative is Belden 8770 (same 18 AWG×3 conductors with Beldfoil®/drain, 300 V, CM) at 2.49 USD/ft.[2][4][7]

Calculation: 2.49 ÷ 5.22 = 0.477… → 0.5 (rounded to one decimal).
Meaning: cheaper equivalent means exist; 88770’s price premium mainly buys FEP/CMP compliance.[2][3][4]

Reliability & Support

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Belden’s documentation and distribution are solid for industrial markets. 88770 clearly specifies CMP, −70 to +200 °C, and other suitability notes (indoor/outdoor, oil/sunlight resistance). No audio-specific measurement guarantees are advertised.[1][6]

Rationality of Design Philosophy

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For installations without plenum or high-temperature requirements, positioning FEP/CMP as an “audio upgrade” lacks scientific basis. Notably, the non-plenum 8770 shows lower conductor-to-conductor capacitance (24 pF/ft vs 54 pF/ft), which is not a disadvantage for long runs. Absent special environment constraints, the cheaper non-plenum option is more rational.[6][7]

Advice

Choose 88770 when you must meet plenum code or face high-temperature/chemical environments. For ordinary audio interconnect runs, Belden 8770 (or similar 3-conductor shielded cables) delivers equivalent transparency at far lower cost. Only in edge cases—very long runs with unusually high source impedance—might cable capacitance be a practical concern.[2][4][6][7]

References

[1] Belden, “Multi-Conductor Cable – 88770”, https://www.belden.com/en/products/cable/electronic-wire-cable/multi-conductor-cable/88770 , accessed 2025-08-21. Construction: 18 AWG (19×30) TC, FEP/FEP, Beldfoil®, 20 AWG drain, CMP.
[2] Belden, “Multi-Conductor Cable – 8770”, https://www.belden.com/en/products/cable/electronic-wire-cable/multi-conductor-cable/8770 , accessed 2025-08-21. 18 AWG (16×30) TC, PE/PVC, Beldfoil®, 20 AWG drain, CM.
[3] Wire & Cable Your Way, “Belden 88770 … per foot”, https://www.wireandcableyourway.com/belden-88770-18-3c-high-temp-plenum-audio-control-instrumentation-cable-shielded , accessed 2025-08-21. Price example: 5.22 USD/ft.
[4] Wire & Cable Your Way, “Belden 8770 … per foot”, https://www.wireandcableyourway.com/belden-8770-18-awg-3-conductor-foil-shield-300v , accessed 2025-08-21. Price example: 2.49 USD/ft.
[5] European Central Bank, “Euro foreign exchange reference rates (2025-08-21)”, https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html , accessed 2025-08-21. Used for JPY conversions on the JA page.
[6] Belden via IEWC, “88770 Technical Data Sheet (PDF)”, https://www.iewc.com/UserFiles/documents/products/be/ld/en/el/ec/mu/lt/ic/on/d8/beldenelecmulticond88770spec.pdf , accessed 2025-08-21. Temperature range, capacitance, DCR, CMP.
[7] Belden via RS, “8770 Technical Data Sheet (PDF)”, https://docs.rs-online.com/af53/0900766b815fd26a.pdf , accessed 2025-08-21. Capacitance 24 pF/ft, DCR, CM.

(2025.8.22)