I can't speak for US standards, however, in Australia on the National Broadband Network the standard for lead-in conduit is P20 conduit (23mm inner diameter with 26.6mm to 26.8mm outer diameter). I imagine in the US it may be something similar. Page 17 of https://www.nbnco.com.au/content/dam/nbn/documents/developers/newdevs/NBN-DE.... Regards, Christopher Hawker ________________________________ From: NANOG <nanog-bounces+chris=thesysadmin.au@nanog.org> on behalf of Sean Donelan <sean@donelan.com> Sent: Thursday, November 23, 2023 4:35 AM To: nanog@nanog.org <nanog@nanog.org> Subject: Re: Outside plant - prewire customer demarc preference For *only* $1,000, the builder is willing to pre-install a smurf tube from the demarc to the central distribution point. But such a deal for 5G.... Since most fiber installs seem to use pre-connectorized cable, without affecting building structure integrity (i.e. 2-inch is too big according to builder), how small is too small? Trade size 1/2-inch, 3/4-inch, 1-inch? Does the FTTH industry have any published standards? This is why I don't help friends troubleshoot PC printer problems :-)