Can the intercom be connected to the elevator’s shared inverter?

In theory yes, but a separate small uninterruptible power supply near the intercom is better, so that a fault in the powerful unit does not shut off the doors. The final scheme is approved by a specialist.

Who must provide internet in the building during an outage?

Network equipment usually belongs to the provider, and backup at the node is its responsibility. The OSBB can negotiate separate terms, but this is formalized by an agreement and with an engineer’s approval.

Backup Power for the Intercom, Internet and Fire Safety Systems

Author: Svitlo-Lux editorial team. Published 2026-10-23, updated 2026-10-23. Review (engineering): approved (Project owner).

The intercom, network equipment, video surveillance and fire alarm draw little power, but without them the building becomes vulnerable: doors fail to open or stay open, communication disappears, and fire signals do not reach those who must respond. Backup power for the intercom and related systems is usually the cheapest part of the whole project.

Inventory: who has their own batteries and who does not

A building’s low-voltage systems belong to different owners: the intercom and video are usually maintained by the OSBB (condominium association) or a contractor, the internet provider’s network node belongs to the provider, and the fire alarm and public address have a separate maintainer. Before planning backup, find out who owns which equipment and what backup power it already has built in.

Low-voltage building systems: what happens without power and who owns them
System	What happens without power	Who is usually responsible	What to ask
Intercom and electric lock	Doors cannot be controlled or stay in the state determined by the lock design	The OSBB or the maintenance company	In what state the lock is held without power and whether there is a backup source
Video surveillance	Recording stops, cameras shut down	The OSBB	Whether recording is needed during an outage
Internet and network equipment	Connectivity in the building is lost, only mobile may work	The provider	Whether the provider has backup at the node in the building
Fire alarm and public address	The control panel loses supervision, the alert does not sound	The safety system maintainer	Backup duration per the design and the battery replacement date
Elevator dispatcher link	A resident in the cabin cannot call for help	The elevator company	How long the link works without the grid

Fire safety: a specialist handles the codes

Fire alarm and public address systems have built-in backup sources, and their parameters are set by the design and regulatory requirements. This page does not quote the requirement figures, because we have not checked them against the current edition of the documents; the rule is simple: the board does not interfere with the power of fire systems on its own, but asks the maintainer to confirm the backup duration and the date of the last inspection.

How much this needs: orders of magnitude

An intercom control unit, a video recorder’s power supply and a small switch consume tens of watts. A hypothetical example not tied to specific models: suppose the intercom system is 30 W, the recorder with cameras 60 W and the switch 25 W, 115 W in total. For 8 hours of backup runtime that is about 0.9 kWh before margins. This is small compared with an elevator, but a stable source with a short switchover is needed, otherwise the devices reboot.

For such loads, compact uninterruptible power supplies near the node are appropriate. Their characteristics and temperature limits are given in the datasheet, and for a building they make sense as a standalone first-phase solution, without waiting for a large project. Details about UPS are covered in a separate guide.

Elevator communication and doors: small things that decide

A resident trapped in a cabin uses the same intercom or dispatcher link that can disappear along with the power. So ask the elevator company whether the link has its own source and for how many hours it lasts. Separately, check how the entrance door behaves: with some locks the door is open without voltage, with others it is locked, and this determines how residents will get home and exit during an emergency.

Internet without power: what is in the OSBB’s hands

The provider’s network equipment in the basement or on the technical floor is usually fed from the building’s grid. If the node is off, the internet in apartments disappears even when residents’ routers run on their own sources. The OSBB can agree with the provider to power the node from a backup circuit, but that is a negotiation and a contract, not technical improvisation. First find out whether the provider already has backup, how long it lasts and what the conditions are for access to the building’s panel.

Ask the provider for information on the backup power of the node in your building.
Record in writing who is responsible for maintaining this backup.
If the node will be connected to the building’s backup circuit, this must be formalized by a contract and approved by an engineer.

Typical mistakes

Installing one large UPS for all low-voltage systems and connecting the fire alarm to it.
Not finding out in which position the electric lock is held without voltage, and not knowing what to expect from the doors.
Not checking battery replacement dates in the intercom control unit.
Forgetting the elevator link to the dispatcher.
Not recording who owns each device, and then looking for someone to blame.

What the board should do

A short plan for low-voltage systems

Draw up a table of systems with their owners and maintainers.
Ask the maintainers for the backup duration and battery replacement dates.
Decide which systems are backed up from a shared source and which independently.
Do not change the power of fire systems without approval from specialists.
Add low-voltage loads to the overall list for the calculation.

Frequently asked questions

Can the intercom be connected to the elevator’s shared inverter?: In theory yes, but a separate small uninterruptible power supply near the intercom is better, so that a fault in the powerful unit does not shut off the doors. The final scheme is approved by a specialist.
Who must provide internet in the building during an outage?: Network equipment usually belongs to the provider, and backup at the node is its responsibility. The OSBB can negotiate separate terms, but this is formalized by an agreement and with an engineer’s approval.

Preliminary backup power calculation Prepare a fundraiser for the OSBB

This material is for general information only and is not a power supply design, legal or financial advice. Calculations are indicative; installation and protection selection must be done by qualified specialists only. The platform does not accept or hold funds.