Fuse Holder Lockout – Product Comparison

Introduction

Red Spot fuses are a style of fuse widely used in industrial electrical distribution boards. ‘Red Spot’ refers to those now manufactured by Cooper Bussman and distinctively marked with a red spot on the visible face of the fuse carrier.

They come in a range of size from 20Amp through 32Amp, 63Amp, 100Amp and 200Amp.

Removal of the fuse carrier disconnects power and this is often used as a method of isolation for workers who need to carry out maintenance or cleaning tasks on the equipment which has been isolated.

While the fuse can be locked away in a safe place, or even kept in the workers pocket, there’s always a risk that other workers, on finding the equipment isolated, could insert another fuse and restore power. The potential consequences of this action can be very serious.

Therefore, a range of lockout devices have been developed by a selection of different manufacturers, all offering the capability of blocking the fuse cavity so the fuse cannot be reinserted. Each version is locked in place with a padlock.

In this review, we look at a 5 different types of fuse lockout which all perform this task to varying degrees of integrity.

1. RS20 – RS100 made by Cooper Bussman. This item is offered as an accessory by the same manufacturer as the Red Spot fuse.
2. UFL2 made by Cirtec Australia
3. FL1 made by Mayo Hardware Australia
4. ELO-FCL185 from Total Lockout
5. LOK6 from Martindale Electric

RS20 – RS100

The RS20 – RS100 is a range of 4 different size lockouts. This is one of two devices reviewed here which offers a mechanical engagement. A small catch rotates to engage a ‘tooth’ in the bottom of the fuse holder. Once engaged it’s secured in place with a padlock. And here the main failing of the lockout becomes clear. Because the device sits down very low in the holder, the only padlock small enough to engage is the type you might use on your suitcase luggage. Such padlocks offer little integrity for safety lockout applications and certainly wouldn’t meet the standard requirements laid down by OSHA regulations. In addition this, unlike the other products reviewed here, you need four different versions to cater for fuses from 20Amp to 100Amp.

UFL2

The UFL2 from Cirtec Australia is a very versatile device and probably the simplest design. The outline shape of the lockout incorporates a slot which drops over the side wall of the fuse holder. Like the RS range above it achieves mechanical engagement on the side wall of the fuse holder by means of a cone-pointed grub screw. Once securely in place, a padlock is fitted which blocks access to the grub screw. While this device is simple and easy to deploy, it’s main weaknesses are that the grub screw inflicts a small amount of damage to the side wall of the fuse holder. For occasional use, this is of no consequence by repeated use might cause the fuse holder to crack and break.  This is the only lockout that we tested which can also fit the 200Amp fuse holder.

FL1

The FL1 from Mayo Hardware is also a simple and easy to deploy device. The lockout sits deep in the holder cavity. Turning a thumbscrew causes two pads to extend side-wards to grip the inner walls of the fuse holder. These pads are made from a softer rubberized material therefore giving excellent grip. Once fully engaged, a flap closes down over the thumbscrew and is locked in the lowered position using a padlock. When fitted the padlock location stands high above the fuse holder. It might prevent the electrical cabinet door closing although this has not been tested.

LOK6

LOK6 from Martindale Electric is a highly visible, bright yellow device and arguably the most complicated with many moving parts. It comprises a sliding body which can compress for the smallest fuse holders, and extend out for larger 100Amp fuse holders. Martindale claim it’s designed to block workers fingers coming in to contact with live terminals but when fully extended large gaps remain. The enthusiastic (or clumsy) worker could still get fingers close to the terminals. Deployment involves turning a thumbscrew until the mechanism grips the side wall of the fuse holder. At this point, the thumbscrew becomes a clamp lever which generates increased grip on the side wall. In this position the padlock can be fitted securing it in place. Once fitted, it feels secure and solid. At one end, the lockout overhangs the fuse by some margin. Where fuse holders are tightly packed in the electrical cabinet, it might not be possible to fit a lockout to all fuse holders.

ELO-FCL185

The last lockout device reviewed here is the ELO-FCL185 from Total Lockout. This is the most recent addition to the market and addresses many of the weaknesses identified in others. Functionally, it is very similar to the LOK6 but here the comparison ends. There is minimal overhang off the ends of the fuse holder. The lockout stands proud of the fuse holder by the smallest amount meaning its possible to close the electrical cabinet door while the lockout is fitted.

Like the units from Mayo and Martindale, this unit attaches to the fuse holder side wall using a clamping/gripping mechanism with a soft rubberised pad. Therefore no damage is inflicted on the holder.

Price comparison

At the time of this review (August 2015) prices range from £14.43 ($19.00) for the LOK6 down to £5.95 ($7.85) for the UFL2. Each device offers something a little different over the others. Choosing the right lockout device will depend on which features are deemed the most important as these criteria can vary from one working scenario to another. For this purpose we have prepare the table below which highlights these operational criteria.