Configured ACS800-U1 the integrator actually has on the BOM
The ABB ACS800-U1-0120-7+L503+N669+P901 is the configured factory build of the ACS800-U1 wall-mount AC drive family, not a base catalog line — the suffixes L503, N669 and P901 are part of the order string the panel was cut for, so any replacement has to carry the same option code or the drive's I/O, control or feedback map will not match the drawings.
Option string drives the wiring diagram, not just the nameplate
Configured U1 builds like this one are exactly the case where the BOM line must read the full +L503+N669+P901 string: the line-side power terminals, the control terminal block, and the encoder / fieldbus option slot are all governed by the option codes, and a base ACS800-U1-0120-7 ordered without them will not land on the same drawing. Sourcing a replacement against the full configured string — not a generic 0120 frame — is the only way the integrator avoids a rewire and a parameter reload, and it is what an RFQ against this code has to specify line by line.
Sourcing posture for a configured and aging line
Sourcing the configured ACS800-U1-0120-7+L503+N669+P901 against a quote is the right move when a line is down or a configured BOM slot has to be filled: it is a drive built to order with a specific option string, and quoting it against the full code lets the supplier confirm the option set is still manufacturable and aligned with the existing panel before the order is placed.