Santon Firefighter Safety Switch 40A 1000V

Description

The Santon DFSHP-14-MC4 firefighter safety switch is a motor-driven 4-pole DC disconnect that isolates up to two PV strings (2 MPPT inputs) at 1000 V DC and 40 A whenever the AC supply to the unit is interrupted. Fitted close to the array, it removes live DC from the cabling that runs through the building, so a firefighter who simply shuts off the AC supply, as on any building, also de-energises the DC run to the inverter.

It arrives pre-wired with 8 original Stäubli MC4 connectors and a 1 x M12 cable gland for the AC supply, in an IP65, UV-resistant enclosure built around Santon's X-type snap-action switch (3 ms disconnect, self-cleaning contacts). It runs from a 100 to 240 V AC supply, restores DC automatically when AC returns and trips to OFF above 100°C internal temperature.

1000 V DC

Rated string voltage

40 A

Rated string current

2 strings

2 MPPT inputs

4-pole

Switches + and − poles

IP65

Weatherproof enclosure

−20 to +50°C

Operating range

Key notes before you specify

Installation and safety

Install only by competent, certified personnel in line with BS 7671 Section 712 (IEC 60364-7-712), MIS 3002 (MCS) and local building regulations. PV modules remain live in daylight and the cabling between the array and this switch cannot be isolated, so mount the unit as close to the array as possible, out of direct sunlight and continuous water ingress. Test the unit after installation by switching the AC circuit off and on, as described in the installation manual.

Check your array against the ratings

One unit handles two strings maximum at 1000 V DC and 40 A per string. Check the string's maximum open-circuit voltage (including cold-weather Voc) and short-circuit current against these limits. Arrays with more strings need one unit per two strings, and 1500 V systems need Santon's 1500 V (Evo2) variant instead of this model.

How it works

The DC contacts are closed whenever AC power is applied to the unit. Interrupt that AC supply with any series-connected device, such as a main isolator, circuit breaker or emergency stop, and the switch opens all four DC poles. When the AC supply is restored, DC reconnects automatically with no manual reset.

Key features

1

Automatic DC shutdown

Opens all four DC poles when the AC supply to the unit is interrupted for more than 0.5 seconds, isolating the DC cables to the inverter.

2

Automatic reset

DC reconnects by itself once AC has been restored for more than five seconds. No manual reset after a power cut.

3

Pre-wired and ready to fit

Factory-fitted 8 x original Stäubli MC4 connectors and 1 x M12 AC cable gland. Wall-mount, plug in the strings and wire the AC supply.

4

Santon X-type snap-action switch

Disconnects in 3 ms with self-cleaning blade contacts to limit arcing. The same switch type many inverter manufacturers specify.

5

Thermal protection

Switches to OFF if the internal temperature exceeds 100°C or on an internal fault. Reset by removing and re-applying the AC supply after checking the installation.

6

Feedback contact and scalable

Normally-open feedback contact (24 V DC, 300 mA max). Fit several units and feed them from one AC circuit for a common DC shutdown on any array size.

Technical specification

DC ratings

Rated DC voltage

1000 V DC

Rated DC current

40 A per string

Poles

4 poles (0-1-0-1)

Strings / MPPT inputs

2

DC switching category

EN 60947-3 Cat PV-1, switching both + and − poles

AC supply to the unit

Operating voltage

100 to 240 V AC

Nominal voltage

230 V AC

Nominal current

30 mA

Start-up (loading) current

100 mA average

Switch-on action current

300 mA maximum

Feedback contact

Normally open, 24 V DC, 300 mA maximum

Switching behaviour

DC off

After AC interrupted for longer than 0.5 seconds

DC on

After AC restored for longer than 5 seconds

Thermal trip

Automatic OFF above 100°C inside the enclosure

Switch disconnect time

3 ms (X-type snap action)

Operations without current

9,700

Operations under load (PV-1)

300

Connections

DC side

8 x original Stäubli MC4 connectors, pre-wired

AC supply

1 x M12 cable gland

Enclosure and environment

Protection degree

IP65, UV-resistant enclosure

Protection class

Class II

Operating temperature

−20°C to +50°C

Storage temperature

−40°C to +85°C

Weight

Approx. 1 kg

Enclosure dimensions

210 x 175 x 105 mm

Mounting

Wall-mounted, as close to the PV modules as possible

Approvals and identification

Certification

CE, EN 60947 parts 1 and 3

Manufacturer part number

DFSHP-14-MC4

Frequently asked questions

How does the Santon DFSHP-14-MC4 work?

It is a motor-driven DC switch powered from the AC supply. While AC is present the DC contacts stay closed. If the AC supply is interrupted for longer than 0.5 seconds the switch opens, breaking the DC connection between the solar panels and the inverter. When AC has been back for more than five seconds, it closes again automatically.

Does it replace the inverter's DC isolator?

No, it adds to it. In most PV systems the DC isolator is built into the inverter, and after it is switched off the DC cables between the modules and the inverter can still carry up to 1000 V. This unit isolates the DC close to the modules, so far less cabling remains live inside the building.

How many strings does one unit handle, and what about larger arrays?

One unit isolates two strings (2 MPPT inputs) at up to 1000 V DC and 40 A per string. For larger arrays, fit one unit per two strings and, if you want a common DC on/off, supply every unit from the same AC source.

Where should I mount it and what AC supply does it need?

Mount it as close to the solar panels as possible on a wall, out of direct sunlight and continuous water ingress. It needs a 100 to 240 V AC supply (nominal 230 V), wired so that it is interrupted when the building's AC supply is shut off. It draws 30 mA nominal.

How do I test it after installation?

Power up and wait about one minute while the internal backup charges. Switch the AC circuit off and the unit should open within about 1.5 seconds. Switch the AC back on and it should close after about 5 seconds. Santon recommends checking the system for faults every three months.

What do I do if it has tripped on temperature?

If the enclosure exceeds 100°C the unit switches itself OFF. Once you have checked the installation and the unit is unaffected, remove and re-apply the AC voltage to switch it back ON. The same reset applies after an internal-fault trip; if the problem persists, contact Santon support.

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