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Cisco Meraki Documentation

MT40 Smart Power Controller FAQ

The Basics

What is MT40? 

MT40 is a BLE-connected, in-line AC-wall powered smart power controller. It allows customers to monitor power metrics, and remotely turn on or off power to the device it is monitoring.

MT40 Top view.

MT40 side profile

What does in-line mean?

In order to monitor and control power for an electrical device, MT40 must be connected between upstream power and the device "in-line" with the device’s power supply. When using MT40 to monitor power consumption of a switch, the MT40 should be plugged into the power outlet, and then the switch should be plugged into the MT40.

AC Power Source ⚡→ (Input) MT40 (Output) → PSU of the device being monitored.

How does MT40 connect to the dashboard? 

Like the rest of the MT family, MT40 uses a compatible MR or MV device as a gateway to wirelessly connect to the dashboard, using Bluetooth Low Energy (BLE) technology.

What does MT40 measure?

MT40 allows customers to monitor several power metrics for whatever is upstream of it. It provides measurements for:

  • Voltage, measured in volts (V)

  • Current, measured in amps (A)

  • Apparent power, measured in volt-ampere (VA) 

  • Real power, measured in watts (W)

  • AC frequency, measured in Hertz (Hz)

  • Power factor, a measure of efficiency as a percentage (%)

  • Energy, measured as kilowatt hours (kWh) 

What can MT40 alert on? 

MT40 can alert when a power metric exceeds or drops below a threshold or when a power outage is detected.

Alerts can be configured to send via SMS, push notification, email, or webhook.

What use cases can MT40 be used for?  

MT40 can be used for a variety of applications. Common use cases are:

  • Alerting on anomalous power readings to prevent downtime: MT40 allows users to set alert thresholds for power readings that exceed normal conditions. This allows users to stay informed about power conditions that could indicate improper equipment configuration or impending device failure

  • Remotely reboot devices: MT40 allows admins to remotely turn on or off devices to help with troubleshooting, eliminating the need to travel to the site, or having to rely on non-technical employees to be able to locate and reboot the device in question.

  • Identifying power outages and enabling a more efficient response to reduce downtime/impact: MT40 can notify customers in real-tie of power outages, and provide insight to where in their infrastructure the outage occurred. This helps shorten time to resolution.

  • Monitor, evaluate and optimize energy costs across devices: MT40 can provide benchmarking for how much energy is being consumed by different devices, and measure the effect of different initiatives to reduce energy consumption. MT40 can also be used to turn off devices when they are not needed to save on energy usage.

What kinds of devices can you use MT40 with?

MT40 can be used to monitor and control power to a wide variety of devices, including point of sales systems, audio/video equipment, printers, lighting, low power HVAC equipment and fans, refrigerators, and more. MT40 allows organizations to monitor energy usage, remotely turn off power to reduce energy when not in use, and remotely reboot devices for troubleshooting. 

Technical questions

How often does MT40 sample data?

MT40 samples all power data every 15 seconds

How often does MT40 send data to the dashboard? 

MT40 sends data to the dashboard either every 20 minutes, or upon an alert threshold violation, or upon a refresh data request made by the user from Dashboard.

How does MT40 detect and alert on a power outage?

The MT40 infers upstream power outage using missed heartbeats. MT40 sends a periodic heartbeat and if no heartbeat has been recorded by any gateways for 5 minutes, the Dashboard infers this as an upstream power outage. Please note that this Alert can be triggered due to one of the following reasons:


  • Upstream power outage

  • Upstream network outage

  • Loss in Sensor or Gateway's dashboard connectivity

  • Sensor firmware upgrade

  • Dashboard service outage

What happens if MT40 goes offline? Does the device it’s connected to lose power?

If MT40 goes offline, it retains the last known power state. For example, if MT40 is configured to turn power ON and it later goes offline, MT40 will keep the power ON status. 

When MT40 goes offline, it will continue to collect and store power data for up to 3.5 hours (900 samples for each metric, at a 15s sample period). If MT40 is offline for longer than 3.5 hours, it will overwrite the oldest data. When MT40 comes back online, it will upload all stored data to the dashboard.

How does the power cycle command work with MT? Is the wait time configurable?

When a power cycle command is sent, it will turn off downstream power, wait 10 seconds, and then turn downstream power back on. This will essentially emulate cold-booting a device by toggling its power input. The 10 second wait period is not configurable. 

What are the power ratings for MT40?

MT40 is rated for up to 250 Volts and up to 12 Amps. 

What type of ports does MT40 have?

On the input side, MT40 has an IEC C14 receptacle. It is compatible with both IEC C13 or IEC C15 plugs. On the output side, MT40 has an IEC C13 receptacle, which are compatible with IEC C14 plugs. 


MT40 plug input, output, and compatibility.

What security features does MT40 have?

Like the rest of the MT portfolio, MT40 has a Cisco Trust Anchor module (TAm) on-board which provides a Secure Unique Device Identity (SUDI). This allows MT40 to securely authenticate as a trusted device, and prevents untrusted devices from communicating with the dashboard. 


For additional details on the security architecture for the MT sensor line, refer to this documentation article

MT40 also has a physical remote lockout switch on the device. When the remote lockout switch is in the locked position, MT40 will ignore any power commands from Dashboard and downstream power will remain on. 

What is the remote lockout switch for?

The remote lockout switch is located on the side of the MT40. The lockout switch allows customers to prevent any power commands (sent from the dashboard) from affecting MT40. Remote lockout should be used in situations where MT40 is monitoring power on a critical piece of infrastructure that needs to remain online at all times, to protect against accidental commands. 

By default, the remote lockout switch is set to the unlocked position out of the box. When it is switched to the “locked” position, power is turned ON if it is not already on. If a user switches it to “unlocked”, MT40 will remain on, but will be able to receive power commands from the dashboard.

Can power data be exported from MT40?

Yes, admins can export up to 7 days of data from the dashboard as a .csv or .xls file. The same data is also available via API and MQTT. 

What mounting options does MT40 support?

Does MT40 have any certifications? 

Yes, MT40 has the following certifications: 

  • UL 60950-1 Information Technology Equipment - Safety

  • UL 62368-1 Audio/Video, Information and Communication Technology Equipment - Safety

Can MT40 be used with a PDU or power strip? 

MT40 can be connected in-line with PDUs or power strips. Keep in mind that if a customer turns the power off on a power strip or PDU, it will override the power on/off state for MT40. 

Can MT40 be used with an uninterruptible power supply (UPS)?

MT40 can be connected in-line with a UPS. In this type of deployment, it is recommended that MT40 be connected downstream of the UPS so that the UPS can protect MT40 against power surges. 

Does MT40 have surge protection? 

No, MT40 does not offer surge protection. If a customer wants surge protection while using MT40, they should use a UPS or surge protector in-line with MT40.

How accurate are MT40 readings? 

MT40 readings are accurate to +/-1% for all metrics.

How long is MT40 data stored in the dashboard?

The dashboard stores MT40 data for two years. Note that only one year of data can be viewed at a time.

Does the MT40 have API support?

Yes. More details on the API endpoints can be found here.

Ordering Info

What is the SKU and license?

MT40-HW: Smart power monitor and controller

LIC-MT-xY: Enterprise License for MT


What comes in the box? 

MT40 includes:

  • Quick install guide with serial number stickers

  • Mounting bracket, screws, and drywall anchors

  • Zip ties for rack mounting

  • Cable management velcro strap

  • IEC C13, C14 retention sleeves

What accessories are available for MT40?

MT40 is compatible with MA-PWR-CORD-XX for input power. This is the same SKU used to power all Meraki equipment.


MA-PWR-C14-C15-1 is used on the output side to connect power to a Meraki, Cisco, or other type of device that accepts IEC C13 or C15 as a power input. 


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