Generally, child car seats come equipped with a 3 point or a 5 point harness in group 0+ seats, and a 5 point harness in a group 1 car seat. The job of the child car seat harness is to restrain the child in the child seat in the event of a collision.
Group 0+ rear facing car seats may have either a 3 point harness or a 5 point harness. In a collision the child is pushed back into the seat, which spreads the force across the whole seat back - putting much less force on the child and better protecting their neck and spine. The job of the 3 or 5 point harness is to hold the child in the seat.
A 5 point harness has additional hip straps to help spread the force of a collision. This is very important when forward facing as the harness takes a lot of force which is then spread across the child’s torso.
The child car seat harness is made up of two long straps, which attach to the buckle. The harness is secured at either end so that it sits over the strongest points of a child’s body – their hips and shoulders.
The hip straps on the harness are attached to the seat by metal hooks (picture below) which slot through a specific gap in the seat shell. These must always be attached completely and it is worth checking the harness is fully attached every journey.
The shoulder straps on the harness attach at the back of the seat, often to a ‘Y’ shaped metal hook (picture below). The straps should always be securely attached and only removed from the hook if you must re-thread the harness to change the harness height position.
Many car seats now come with a harness that you can simply click into a different height position, removing the need to unhook it – this removes the very high risk of the harness being misused.
Each harness strap will have a plastic attachment on it, which joins together to click into the buckle.
To set the correct harness height, the straps must come over the child's shoulders and down towards the buckle. The harness must be level with the child's shoulders, although this isn't always possible. If you can't get the straps level with the child's shoulders (due to them being between height limits, for example) then the following is how you can figure out the best height:
Rear facing: Level with, or just below the shoulders.
Front facing: Level with, or just above the shoulders.
You should be able to get two fingers flat between your child’s chest and the harness at collar bone level.
The pads on the straps of a car seat normally need to be pulled down the straps so they sit on the child's chest. You will often find the pads are attached to fabric, which ensures they are pulled down to the correct height.
The pads on this seat need to be pulled down onto the child's chest.
Other harness pads are attached to the top of the child seat, and will sit over the child's shoulders.
The pads on this seat are attached to the top of the harness
Every car seat in the UK which has a 3 or a 5 point harness must have a buckle to click into. Both pieces of the harness must come together first, before clicking into the buckle. This is to ensure that both parts of the harness are always attached. The button of the buckle is stress tested to ensure it can withstand the thousands of clicks and un-clicks it will go through in its lifetime. The buckle is also pressure tested to ensure most little fingers can’t un-click it, but that it is also easy to undo in an emergency.
What children wear when they go in the car differs with each journey, for this reason it is useful to loosen the straps before you take your child out of the car seat – the next time you buckle your child in you can pull the straps tight to ensure the correct tension every journey to suit what your child is wearing.
Puffy winter snowsuits, coats and jackets can cause big problems with the car seat harness – they should never be worn under the harness. The harness is designed to fit close to the child’s body, and it is tested in this way. Puffy snowsuits, coats and jackets create a gap between the child and the harness. Even if the harness feels as though it is pulled tight, in a collision it may still not work properly.
Children should be wearing light, thin layers when in the car seat – a thin fleece at the most. Remember, children heat up 3-5 times faster than adults and they do not regulate their body temperature as well as adults. It is very easy for babies and children to overheat in the car; so don’t be tempted to pad them out – your vehicle will soon heat up leaving you with a very hot and sweaty little one for the rest of your journey!
Car seats become grubby very quickly and wiping over them with a damp cloth isn’t always enough and a full wash is required! It is very important that the harness is not washed, as this can break down the fibres within the harness and weaken it.
When cleaning the buckle, again wipe over it with a damp cloth and remove any food that is in or around the buckle and red button – hoovering the buckle helps ensure most of the crumbs and muck is removed.
Some car seats have easy to remove covers and you don’t have to remove the harness at all to get the cover off – however there are still lots of car seats where you do need to remove the harness to get the cover off!
When removing the covers, it is very easy for the harness to become twisted or incorrectly routed or fitted. When you are taking the cover off, as often as possible, re-thread and attach the harness back where it is supposed to go to help avoid it becoming incorrectly routed or twisted.
This is extremely frustrating to any parent or carer; and very scary the first time the little one finds out they can do it! Some children will learn to undo the harness buckle, even with the regulated amount of force it must take to pop the buckle open.
1) Check the harness height – if the harness is too low, children can ‘wedge’ their shoulders under the straps and use the force to push down on the buckle.
2) Check the harness tension.
If your child continues to undo their buckle and they don’t seem to be growing out of the habit, you may want to try them in another weight suitable child restraint to see if they are less able to unclick the buckle on that seat.
A child un-clicking the buckle is not a good reason to move them up to a high back booster and adult seat belt, especially if they are below the weight or height limits.
As with the above issue, this happens very often! First things to check:
1) Harness height – is the harness at the correct level?
2) Harness tension – is the harness too tight or loose on the child?
3) Clothing – is the clothing allowing a gap for the child to wriggle their arms through? Thick and puffy jackets often cause this!
4) There are some after market products you can try with your seat, that are designed to stop children wriggling out of the straps. If you choose to try an aftermarket product, ensure you read and fully understand the instructions of use before using it with your child's car seat. Also make sure that it is not interfering with the way the harness sits on the child.
Maxi Cosi recommends the '5 point plus' for use with their car seats.
If the child continues slipping the harness, try them in a different weight appropriate restraint to see if they will wriggle the straps off in that seat.
A child wriggling the straps off is not a good reason to move them up to a high back booster with adult belt – especially if they do not meet the weight or height limits.
If your child does not seem to be growing out of the habit of removing their straps or un-doing the buckle, an impact shield style seat may solve the issue. These seats do not use a 5 point harness, but a “shield” is placed across the child.
Hello! Would it be possible to include some information on the position of the pads that slide up and down the harness straps? I have seen various parents positioning them at the shoulder and I'd like to refer them to a reliable source of info. Thanks!
Thanks for your comment!
The chest pads need to be positioned on the chest of the child - quite often, the pads will be attached to fabric, so they pull down to the correct level. Some child seats may be different, and have the pads attached at the top of the seat. In this case, they remain attached at the top and will come across little ones shoulders.
We'll add this information into the blog - thanks for highlighting it!
The Good Egg Team
Great article - I have another question on shoulder pads!
We have a seat where the straps are attached to the seat body, to ensure they sit at the correct height (on top of the shoulders of the child as per your picture above). I'm finding, though, that - even when the belt is pulled tight - the thickness of the pads means that I can easily slip my hand between my child's chest / tummy and the straps (once the straps emerge from the routing on the shoulder pads). Looking at your picture, it seems that this may be normal, but seems a little odd to me - don't the pads just create a similar problem to a child wearing a bulky jacket?
Thank you for your comment, and we're glad you enjoyed it!
The correct tension of the belt is tested at the child's collar bone level, the straps must be tight enough so that you can just get two fingers flat between the straps and little one. This tension then allows the harness to spread the force of a collision over their strongest parts - their hips and shoulders. The chest pads are specially designed to also absorb energy away from little one's chest, to reduce loading. A puffy coat creates a gap all over, which is part of the danger.
The gap by their tummy is created by the buckle itself and the way the harness routes through the buckle. Providing the harness is nice and tight across their hips and shoulders, and the harness is not slack by their tummy, there is no danger to little one's
The Good Egg Team
Hi. Great artical.
I think I may of been pulling straps too tight on my children as I've read it elsewhere that it has too be one finger on the chest (which is really hard to get so tight) is there any risk to pulling them tighter than 2 fingers on the collarbone? Thanks.
Thank you for your comment
When pulling the straps tight, the two fingers need to be flat between the child's collar bone and the harness. So whether you test with one finger or two, so long as you can get the finger/s flat between the harness and the child, the straps are tight enough. You can't really pull the straps too tight, they need to be tight to your little one to properly absorb energy from a collision
The Good Egg Team
Hi thanks for this helpful website. Can I ask if there is any guidance about whether the baby has to be strapped into the chair if sitting there but not in car? Our baby fell asleep so we put the car seat into our pram chassis and took her into the restaurant. I thought she'd be more comfortable without the straps so undid her. I was watching her and right next to here but I was told off for not having her strapped in! Safety wise was I wrong?
Thank you for your comment and we're glad you find the site helpful!
Whenever your baby is in their infant car seat, even when they're not in the car, the straps should always be secured to little one.
The Good Egg Team
Hello, thanks for this brilliant article -it answered my question about shoulder / chest pads! However, we are having the problem that the straps are cutting into my little ones neck causing sores and on one occasion breaking the skin, I had considered wrapping a muslin cloth around the strap but wasnt sure if this was reduce the safety of the seat/straps? Is there anything I can do to stop this -it has the pads that pull down to cheat level. Thanks.
Thank you for your comment.
A small muslin cloth will not alter the effectiveness of the harness, provided it is thinly over the strap - much like a hood on a jumper would be. The cloth should not interfere with the way the harness fits on little one, and the straps should still be able to be pulled tight to little one's chest.
The Good Egg Team
Thanks for this great article. Very helpful and informative. I do have a question in the pad that sits on the buckle. If this is lost, does it affect the safety?
Thank you for your enquiry!
Ideally, the straps should always be level with the shoulders, regardless of what direction little one is facing. However, this isn't always possible, for example, if little one is between strap heights. In this case, you go just above when forward facing, so they are held back into the seat. When rear facing, you go just below, as they will 'ramp' up the seat in an impact, and straps that are too high will cause them to slide up too far and potentially sustain head or neck injuries.
We hope this helps!
The Good Egg Team
My daughter has narrow shoulders and I'm never satisfied that her straps won't move down the arms despite following all guidelines, is there anything I can do?