You can likely get most of what you need from a good AI chatbot and then check the applicable electrical code. Chatbots make errors and can sometimes lead you “down a garden path”
From: Boštjan Glavič <[email protected]> Sent: February 27, 2026 11:02 AM To: [email protected] Subject: Re: [PSES] CATV standard in USA I was told that in EU it is 65Vac and in US max 90Vac. AI says following Voltage distributed on the CATV coax (plant power) In North American cable networks, active devices (line amplifiers, nodes, etc.) are powered through the coaxial cable using AC: 60 VAC – very common 90 VAC – also widely used, especially for longer cascades or higher power loads These voltages are AC, injected by a CATV power supply and carried on the hardline coax together with RF signals 12. Typical characteristics: Frequency: 60 Hz AC Carried on hardline coax (e.g. .500, .625, .750 cable). Used exclusively for powering outdoor CATV active equipment. Sent from Outlook for Android <https://aka.ms/AAb9ysg> <https://www.siq.si/en/> <https://www.linkedin.com/company/siq> <https://www.youtube.com/channel/UCURzJFvP5CDVtL_vdvWjbQA/featured> <https://www.facebook.com/SIQLjubljana/> Boštjan Glavič Vodja laboratorija za elektroniko / Head of Laboratory Varnost in elektromagnetika / Safety and Electromagnetics SIQ Ljubljana T <tel:+386%201%204778%20265> +386 1 4778 265 / <tel:+386%2041%20391%20283> +386 41 391 283 E <mailto:[email protected]> [email protected] W <https://www.siq.si/en/> www.siq.si A Mašera‑Spasićeva ulica 10 , Ljubljana , Slovenija , SI‑1000 To elektronsko sporočilo je namenjeno izključno naslovniku. <https://www.siq.si/pravno-obvestilo-za-prejemnike-elektronske-poste/> Pravno obvestilo. The information transmitted by this email is intended only for the person or entity to which it is addressed. <https://www.siq.si/en/legal-notice-for-e-mail-recipients/> Disclaimer. _____ From: John Woodgate <[email protected] <mailto:[email protected]> > Sent: Friday, February 27, 2026 7:40:01 PM To: [email protected] <mailto:[email protected]> <[email protected] <mailto:[email protected]> > Subject: Re: [PSES] CATV standard in USA CAUTION: This email originated from outside of our organisation. Do not click links or open attachments unless you recognise the sender and know the content is safe. For 90 V AC, you would need to check the voltage rating of the connectors, too. Probably lower than that of the coax. On 2026-02-27 18:22, Ralph McDiarmid wrote: I find the phrase, “supplied by a transformer or other device that has power-limiting characteristics” as unhelpful and unsatisfactory. A quantity like, 100 VA, would clarify the requirement. The Code‑Making Panels (CMP) and the Technical Correlating Committee (TCC) who create the NFPA 70 document are supposed to know better. For CATV using with inline amplifiers for signal leveling, the power caried in the coax can be up to about 18 Vdc and 500 mA. If you’re pushing 90 Vac on a coax, then you will need to look up the rated voltage for that coax and whether that rating is regulated by 3rd party. (e.g. UL or TUV or CSA ….) it would not be treated as Class 1, 2, or 3 as in signalling control, doorbells, and alarms system circuits. Ralph From: John Woodgate <mailto:[email protected]> <[email protected]> Sent: February 27, 2026 3:34 AM To: [email protected] <mailto:[email protected]> Subject: Re: [PSES] CATV standard in USA 'Not over 60 V' does not allow 66 V. The limit implies 54.5 V ± 10 %. On 2026-02-27 11:10, Boštjan Glavič wrote: Dear experts, I would again need your advice. We are testing the product, that is supplied through remote CATV network via coax cable. Manufacturer would like to put on the product 90Vac rating. My questions are: - what voltages are actually used in USA for CATV? In EU we normally use max 65Vac. - how is the supply voltage generated (what are requirements for power sourcing equipment)? - can supply voltage fluctuate, similar like ac mains voltage? For normal AC mains we expect fluctuation +/-10%. - should +/- tolerances to 90V be applied? I found below text in NEC 2017, which says something about 60Vac. Is this 60V fixed value or tolerances are allowed (like 66V)? 820.15 Power Limitations. Coaxial cable shall be permitted to deliver power to equipment that is directly associated with the radio frequency distribution system if the voltage is not over 60 volts and if the current is supplied by a transformer or other device that has power-limiting characteristics. Power shall be blocked from premises devices on the network that are not intended to be powered via the coaxial cable. Thank you for your valuable support. Best regards, Boštjan <https://www.siq.si/en/> <https://www.linkedin.com/company/siq> <https://www.youtube.com/channel/UCURzJFvP5CDVtL_vdvWjbQA/featured> <https://www.facebook.com/SIQLjubljana/> Boštjan Glavič Vodja laboratorija za elektroniko / Head of Laboratory Varnost in elektromagnetika / Safety and Electromagnetics SIQ Ljubljana T <tel:+386%201%204778%20265> +386 1 4778 265 / <tel:+386%2041%20391%20283> +386 41 391 283 E <mailto:[email protected]> [email protected] W <https://www.siq.si/en/> www.siq.si A Mašera‑Spasićeva ulica 10 , Ljubljana , Slovenija , SI‑1000 To elektronsko sporočilo je namenjeno izključno naslovniku. <https://www.siq.si/pravno-obvestilo-za-prejemnike-elektronske-poste/> Pravno obvestilo. 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