The short answer is that switching time is how long a transfer switch takes to move your load from one supply to another. ATS switching time explained in one line: under 4 seconds suits a home, pump or office that can wait a few seconds, while under 50ms suits 3-phase machinery that must keep running through an outage. This guide is for anyone choosing between the two TOMZN units here, and it will show you which one fits your installation and what to check before you buy.
Tomzn TOQ7-100 4P 100A 3-Phase ATS
Tomzn TOQ7 100A automatic transfer switch built for 3-phase power.
What does switching time actually measure?
Switching time is the gap between the grid dropping and the backup supply being connected to your circuits. Everything wired to the switch sits dead during that gap, so the number tells you how long your equipment waits.
Under 4 seconds, as on the TOMZN TOQ3-125, is a pause you can count. Lights go off and come back, a pump motor stops and restarts, a computer may reboot.
Under 50ms, as on the Tomzn TOQ7-100, is a blink. Milliseconds are thousandths of a second, so under 50ms is faster than most people can react. The trade is that the TOQ7 is built for a narrower job, 3-phase generator to KPLC changeover, with no solar input.
Which sites suit the under 4 second switch?
The under 4 second switch suits single-phase or three-phase sites where a short break in supply is tolerated. The TOMZN TOQ3-125 is rated 125A and 4-pole, running at 230V single-phase or 400V three-phase.
It takes a generator and the grid, and it also accepts an inverter supply, so one unit can cover a changeover that includes an inverter.
Homes, water pumps and office buildings running on either single or three-phase supply are the cases it lists. A pump restarting after a few seconds is normal for that kind of site.
Fit is the first practical check: it mounts on DIN rail. Before you buy, confirm your distribution board has room for a DIN rail unit of that size, and confirm your supply is a 4-pole arrangement so all poles get switched.
Which sites suit the under 50ms switch?
The under 50ms switch suits 3-phase sites where machinery should not stop. The Tomzn TOQ7-100 is rated 100A and 4-pole, switching all three live phases plus neutral together, which matters for keeping 3-phase motors isolated during a changeover.
A workshop or small factory running 3-phase machinery through a grid outage is the realistic fit. Because the changeover happens in under 50ms, the machine sees a brief interruption rather than a stop and restart.
It takes a generator and the grid only. If you plan to add an inverter or solar supply to the same changeover, this unit does not cover that, so the TOQ3-125 is the one that lists an inverter input.
Both units have a manual mode for testing and maintenance, and both mount on DIN rail. The current rating differs, 125A against 100A, so match the unit to the load your installation carries.
| Feature | TOMZN TOQ3-125 125 Amp Automatic Transfer Switch | Tomzn TOQ7-100 4P 100A 3-Phase ATS |
|---|---|---|
| Product | ||
| Price | KSh 7,800 | KSh 6,000 |
| Rated Current (A) | 125 | 100 |
| Switching Time | Under 4 seconds | <50ms |
| Suits | Homes, water pumps, or office buildings running on either single or three-phase supply | Workshops or small factories running 3-phase machinery that needs to keep running through a grid outage |
| Link | View & Buy | View & Buy |
What should you check before you buy?
Start with the load and the supply, then work through the rest. Write the answers down before you compare models.
- Whether your site is single-phase 230V or three-phase 400V, since one unit covers either.
- How many poles you need to switch, and whether neutral is included.
- Whether an inverter or solar supply forms part of the changeover.
- Whether your panel has DIN rail space for the unit.
- How much your circuits draw against the 125A or 100A rating.
If the answers point to a 3-phase workshop with no inverter, the faster unit is the match. If they point to a home, pump or office with a mix of sources, the under 4 second unit covers more.
You can see the whole range on the ATS Automatic Transfer Switches category page if you want to browse before deciding.
ATS Automatic Transfer Switches
Does a faster switch mean a better switch?
No. A faster switch is the right switch only where the load needs it. Each unit here is built to a different job, and the ratings and inputs differ as much as the times.
What decides the fit is the supply, the load and the sources you want to switch, not the number alone. A home or office that can restart in a few seconds gets the inverter input and the higher 125A rating from the slower unit.
The honest limit on both: neither unit is a power source, and neither one corrects a supply that is already stretched.
Who are these switches not for?
Be clear about the limits before you commit. If your changeover needs a solar input, the Tomzn TOQ7-100 does not cover it, and the TOQ3-125 is the one that lists an inverter supply. If your load must never pause at all, under 50ms is still a break, not a seamless supply, and neither unit is a substitute for a properly sized backup source.
Neither switch is a fix for an installation that is already overloaded or badly wired. If you are unsure about the supply, the pole arrangement or the load, bring in a qualified electrician before you fit anything.
Where would you actually use one?
If you are still deciding, compare your board and supply first, then pick the unit that matches both rather than the faster number.
Which one should you pick?
Pick the TOMZN TOQ3-125 125 Amp Automatic Transfer Switch if
- You need a 125A 4-pole switch for a home, pump or office.
- Your changeover includes an inverter as well as generator and grid.
Pick the Tomzn TOQ7-100 4P 100A 3-Phase ATS if
- You run 3-phase workshop machinery that must keep running through an outage.
- Your changeover is generator to KPLC only, with no solar input.
Where you would use it
- Home backup Keep lights and the house supply running from a generator or inverter when the grid drops.
- Water pump Restart a pump after a short grid outage without walking to a changeover switch.
- Office building Keep office equipment on supply by switching to backup in under 4 seconds.
- Workshop machinery Hold 3-phase workshop machines through a grid outage with a changeover in under 50ms.
- Small factory Switch all three phases plus neutral together during generator to KPLC changeover at a small plant.
Frequently asked questions
It is the time between one supply dropping and the backup supply taking over the load. The TOMZN TOQ3-125 switches in under 4 seconds, while the Tomzn TOQ7-100 switches in under 50ms.
Not on its own. Under 50ms suits 3-phase workshop machinery that needs to keep running, while under 4 seconds suits homes, pumps or offices that can pause briefly.
No. The Tomzn TOQ7-100 covers generator and grid input only, with no solar input. The TOMZN TOQ3-125 accepts a generator, grid and inverter supply.
Yes. Both units have a manual mode so you can force a changeover for testing and maintenance.
Yes, both mount on DIN rail. The TOMZN TOQ3-125 is 125A and 4-pole, while the Tomzn TOQ7-100 is 100A and 4-pole.
Speed is only one line on the datasheet. Match the unit to your supply, your poles and your sources, and the switching time becomes an easy decision rather than the whole decision.
