Latch bypass AKA Carding AKA Jimming AKA Hall pass
### What is it?
A latch bypass is a covert method of entry used to open non deadbolt doors that swing towards you, making it ideal for entry into restricted areas. All external doors will be openable this way as they must swing outward due to fire code. All fire stair doors will be openable from inside as they must swing in toward the stairwell. Most roof doors will also be openable this way.
### Locking Mechanism
There are two main types of locks this will work on:
The first type looks like this
and is characterized by a small rounded latch with a second switch as a part of the latch. The main latch is designed to retract on pressure which allows the door to be closed without turning the handle. The second latch is the dead-locking latch. When this is pushed in the main latch will not retract into the door when it's pushed. You can test this yourself on an open door. This is typically used on very low security areas as it's no a particularly efficient mechanism.
The second type looks like this
. You can clearly see that there is a latch, and the dead-locking latch is a separate component above or below the latch. This means that the dead locking latch is supposed to be depressed by the door frame not within the hole for the latch.
One of the important features is the shape of the latch. Taking an angled edge allows the doors to be pushed closed and fit the latch into place as the latch will retract into the door body which is what allows for the bypass.
### Where is this applicable?
Most doors can be opened with this method. Any door with a maglock, large blocking plate
, or door frame covering the latch. The blocking plate pictured can be bypassed, however some areas have whole door plates which cannot be bypassed with this method.
This is not legal in any states of America or indeed in any countries that I know of. Not only do you face trespass charges but potentially burglary and breaking and entering charges so it's something to be aware of.
There are a few ways of doing this but there are two components, both of which can be replaced with many different pieces of equipment:
- Air wedge/Screwdriver/Crowbar
- Wire/Hall Pass/Slim Jim
If you use wire, it can also be used to defeat a blocking plate, however a stiff wire works best, such as magnetic wire
or similar firm wire.
The purpose of the air wedge etc. is to widen the gap between the door and the door frame so as to take any pressure of off the dead-locking latch and thus allowing the latch to retract in as it would as you close the door.
The purpose of the wire etc is the hook onto the latch itself and apply pressure so as to make it retract, opening the door for you without messing with the lock.
### Method - No Blocking Plate Here is someone performing a latch bypass
with a jim. You can see them push the jim into the doorway and position the cutout over the latch, and then push it down to contact the latch, then pulling it toward themselves to force the latch to retract thanks to the angled edge. This lock did not have a dead-locking latch and thus a screwdriver or airwedge was not required.
The method has 4 easy steps:
1. Locate the latch and dead-locking latch. Place the screwdriver or air wedge above the dead-locking latch if it's above the latch, or below the dead-locking latch if it's below the latch -- basically as close as you can without sacrificing access to the latch itself. With a screwdriver you want to push it through as far as you can without damaging the door. Make sure you are pushing it through where it still contact the metal part of the door frame which prevents damage to the door.
2. Loop your wire around the latch (this is why you need stiff wire, a soft wire that can hold a straight line will be hard to work with, especially when dealing with a plate) and hold the two end of the wire, or place your slim jim/hall pass on the latch with the sharp angled side on the angled side of the latch.
3. Push the screwdriver handle toward the door jam - this means it will press against the metal that has been installed on the door where the latch goes instead of damaging the door. The far end will push the door away from the door frame, creating space and relieving pressure from the dead-locking latch. This may take several attempts to get right, especially the positioning and depth. If using an air wedge, inflate it.
4. While maintaining pressure pull the wire/jim/hall pass toward yourself. This will push the latch back into the door and the door should open.
congratulations you did it!
### Method - Blocking plate
If there is a blocking plate you can still do this method provided the plate isn't too large. You will need stiff wire that can hole a 30cm straight line.
A blocking plate is usually installed because the management is aware of attempts to gain access to the roof/plant room etc but is often also an indicator that the door has been incorrectly installed and the dead-locking latch does not work.
You want to insert the wire into the space between the door and door frame on top of the blocking plate pushing it deep enough that it will go behind the latch. Push the wire through until it pops out the bottom, you may need something like a screwdriver to pull the wire back toward you.
Next you want to do what you did above but first try just pulling the wire. You will feel pressure on the latch if it works. If you missed the latch it'll slip forward and you'll just be pulling on the plate which means you need to reinsert the wire.
If this doesn't work it means the dead-locking latch is functional so you need to create space either with an air wedge or a screw driver. However, often you are too far away from the dead-locking latch for it to be effective so you may need a crowbar. This is usually the point where I'll pick a different entry method.
### Closing words
This method is well known so I feel sharing it online is not going to be a detriment to the community. This method can, however, cause problems. Toys who don't know what they're doing will chew up doors and door frames due to not thinking which alerts staff to their attempts. You must also carry burglary tools which is a major negative.
#### Vicinity, AU