Light Review: Nitecore’s Explosion Proof EF1

With the EF1, NITECORE have confidently entered the market for hazardous environment equipment, with a light which can be used in the petroleum exploration, petrochemical and chemical industries, as it is rated as a Type II non-mine explosion-proof electrical appliance.

 photo 00 EF1 Feature P1200195.jpg

Taking a more detailed look:

The EF1 arrives in a box like the ones used for the TM series.
 photo 01 EF1 boxed P1200173.jpg

Closed cell foam is used as the liner.
 photo 02 EF1 box open P1200177.jpg

With the EF1 you get a holster, lanyard, spare o-rings and the instructions.
 photo 03 EF1 box contents P1200185.jpg

The EF1 in its holster.
 photo 04 EF1 holster P1200188.jpg

On the back it has a fixed loop, a D-loop and a Velcro closed loop.
 photo 05 EF1 holster loops P1200191.jpg

It is a chunky light, but that is due to its heavy build for the Explosion Proof rating.
 photo 06 EF1 angle P1200197.jpg

The lens is very thick making it look like a dive light.
 photo 07 EF1 lens P1200203.jpg

On the side it proudly states its explosion proof status.
 photo 08 EF1 engraving P1200205.jpg

There are a couple of exposed screws on the head that seem to hold parts of the magnetic switch together.
 photo 09 EF1 screw P1200207.jpg

The switch is a rotating/sliding switch with four positions.
 photo 10 EF1 switch P1200210.jpg

It is difficult to really show how thick this lens is, but it is thick – 10mm thick.
 photo 11 EF1 lens P1200220.jpg

A view from the tail-cap end.
 photo 12 EF1 tail view P1200227.jpg

Inside the tail-cap is a spring and ring terminal.
 photo 13 EF1 tail contacts P1200235.jpg

That is one thick battery tube with a minimum thickness of 3mm.
 photo 14 EF1 battery tube P1200237.jpg

A long section of well lubricated standard threads are used for the tail-cap. They are fully anodised, so you can physically lock out the EF1 by unscrewing the tail-cap slightly.
 photo 15 EF1 battery threads P1200245.jpg

With a battery being inserted you see how thick that battery tube is.
 photo 16 EF1 battery insert P1200248.jpg

Peering deep into the battery tube for a view of the positive contact.
 photo 17 EF1 head contacts P1200256.jpg

The XM-L2 U3 LED sits in a smooth reflector.
 photo 18 EF1 LED P1200261.jpg

It is a relatively deep reflector to focus the beam.
 photo 18 EF1 reflector P1200264.jpg

Next to an 18650 cell you can see the heavy build of this light.
 photo 19 EF1 size P1200286.jpg

Slightly surprisingly, the head does unscrew giving access to the reflector and LED. This may be to provide access to the o-ring to allow it to be inspected.
 photo 20 EF1 head off P1200290.jpg

The detail of those threads for the front part of the light.
 photo 21 EF1 head threads P1200291.jpg

The beam

Please be careful not to judge tint based on images you see on a computer screen. Unless properly calibrated, the screen itself will change the perceived tint.

The indoor beamshot is intended to give an idea of the beam shape/quality rather than tint. All beamshots are taken using daylight white balance. The woodwork (stairs and skirting) are painted Farrow & Ball “Off-White”, and the walls are a light sandy colour called ‘String’ again by Farrow & Ball. I don’t actually have a ‘white wall’ in the house to use for this, and the wife won’t have one!

Starting off indoors, the EF1’s beam is narrow overall. There is a relatively average sized hotspot, but only a very narrow spill around this. This appears much more suited to inspection duties than general lighting for getting around.
 photo 23 EF1 indoor beam P1230323.jpg

Giving it some more range outdoors and that narrow spill is still an obvious characteristic.
 photo 28 EF1 outdoor beam P1240708.jpg

Modes and User Interface:

Nitecore have kept the interface of the EF1 very simply. There is a four position sliding switch, OFF (0), Low (1), Medium (2) and High (3).

Simply slide the switch to the position you want. There is nothing more to it.

Batteries and output:

The EF1 runs on either 1x 18650 or 2x CR123.

To measure actual output, I built an integrating sphere. See here for more detail. The sensor registers visible light only (so Infra-Red and Ultra-Violet will not be measured).

Please note, all quoted lumen figures are from a DIY integrating sphere, and according to ANSI standards. Although every effort is made to give as accurate a result as possible, they should be taken as an estimate only. The results can be used to compare outputs in this review and others I have published.

___________________________________________ ________________________________ ________________________________
EF1 using specified cell I.S. measured ANSI output Lumens PWM frequency or Strobe frequency (Hz)
___________________________________________ ________________________________ ________________________________
High – NL189 729 0
Medium – NL189 341 100
Low – NL189 5 217

* Beacon and Strobe output measurements are only estimates as the brief flashes make it difficult to capture the actual output value.

Peak Beam intensity measured 13900 lx @1m giving a beam range of 236m.

There is parasitic drain which varies between 2.68 and 1.2 mA. When using a 3100mAh 18650 it will take 48-108 days to drain the cell. This is very bad for a standby light.

Initially I was testing the EF1 with an Xtar 3100mAh 18650, but the output figures were not up to specification. Subsequently I re-ran these tests with a Nitecore NL189. With the NL189 the ANSI output was higher, but as you can see the runtime was overall lower. Output is not regulated and drops off during the entire run. In the environments in which you would use this light, you definitely don’t want a sudden drop in output at the wrong time, so this is a better runtime profile to have.
 photo EF1 runtime plus Xtar.jpg


This section is included to mention any minor niggles I come across during testing, in case the information helps anyone else.

No issues were encountered during testing.

As per the description of this section, this information is provided in case anyone else finds a similar ‘issue’ that might be fixed in the same way.

The EF1 in use

Before we get any further we must clarify what ‘Explosion proof’ actually means. Firstly, it does not mean you can drop a bomb on it! Instead it relates to the world of hazardous environment equipment, for which there are many different and very specific standards for the various classifications of hazard. The safest equipment are ‘Intrinsically Safe’ devices which are intrinsically incapable of igniting hazardous atmospheres even if destroyed, as no component within them can achieve ignition, including the cells. Then there are the ‘Explosion-Proof’ ratings where the device does indeed contain enough energy to ignite explosive gasses, but critically, should the device have been opened in that hazardous atmosphere and contain an explosive mixture which can be ignited, if there is a small explosion within the device, that explosion is completely contained and cannot propagate into the surrounding atmosphere. The ‘Explosion Proof’ rating is protection from internal explosions.

Now we have got that clear, a direct consequence of the explosion proof rating is that the build is very heavy. Putting the EF1 next to a two cell light, the P36 shows how even though it is a single 18650 light, it really has presence. We are looking at one very tough light.
 photo 22 EF1 size p36 P1200296.jpg

With it being a very solid build, and having a sliding switch, actually the EF1 could also be very suited to diving use. While carrying out my Dive Knives 2016 – Mega Test Review I also took the EF1 with me, but wasn’t able to get any in-use shots. It was ceratinly taken to depths greater than the 1.5m specified, but not more than 10m where I was diving.
One thing I did put the EF1 through was the dive knife corrosion testing (details in the Dive Knives 2016 – Mega Test Review) and this is what happened to the EF1.
Taking in the overall view, the most obvious sign is a small white patch on the handle.
 photo 24 EF1 corrosion P1230810.jpg

Going in closer we can see this is a patch of aluminium corrosion from the salt water exposure. There must have been a small flaw in the anodising for this to have happened.
 photo 25 EF1 corrosion P1230823.jpg

Just next to one screw on the head was a rainbow like colouring on the anodising looking like an oil film. It was perfectly dry and free of oil, and this was only visible after the corrosion test.
 photo 26 EF1 corrosion P1230817.jpg

The last visible effect was that the grease around the sliding switch turned a dark brown/black colour, so was not an inert grease.
 photo 27 EF1 corrosion P1230820.jpg

There were no issues with the EF1 following this intensive corrosion test, and it is still functioning perfectly.

Though we tend to prefer smaller and easier to carry lights, there is a certain satisfaction to carrying the tank-like EF1. Its weight is comforting and there is nothing fragile about it. The slider switch is positive and simple to use and needs no explanation. There is a noticeable delay in the switch response, most notable when switching the EF1 on from OFF. It is probably only 0.3s or thereabouts, but you move the switch, then the EF1 turns on after that brief pause. The same when changing levels.

For my own use, the biggest issue is the mode spacing. It has a useful 5lm Low mode, but then jumps to 341lm. It definitely could have done with something around 80lm-100lm mark instead of jumping right up to 340lm. When the 5lm is not enough, that jump can be blinding.

Not working in a hazardous environment myself, I can’t say if the beam profile is a good fit for this type of use. It certainly seems to be an inspection type of beam rather than one for general use and getting about. I found it too narrow for navigating on rough ground as the hotspot was giving peripheral blindness when shining it at the ground. It is fine for longer distances, just not good closer up.

For the domestic user, there is the attraction of the Explosion Proof rating particularly in case of gas leaks. Personally I have several gas-safe lights including intrinsically safe lights. Those intrinsically safe lights however are all AA Alkaline powered, so the EF1 with its Li-ion power means the output is much higher, and I would consider it totally safe to use in a domestic gas leak situation. Some users would argue that any waterproof light will be safe to use, but this is wrong. If you change the battery and the explosive atmosphere gets inside the light, turning it on could create an explosion that would break out of a normal waterproof light. It would have been fine if you hadn’t opened it, but you did. With the EF1 this would not matter, as if this internal explosion did occur, the EF1 can withstand it – I know what I’d rather be holding.

Review Summary

_______________________________________________ _______________________________________________
Things I like What doesn’t work so well for me
_______________________________________________ _______________________________________________
Explosion Proof rating. Big jump in output from Low (5lm) to Medium (341lm).
Simple sliding switch. High parasitic drain – remember to lock out the tail-cap.
Predictable gradual drop in output (no sudden cut-out). Narrow spill limits versatility.
Extremely solid build. PWM used on Medium and Low modes.
Excellent corrosion resistance.
Holster supplied.

 photo 00 EF1 Feature P1200217.jpg


Discussing the Review:

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