Defibrillator installation

[pirate]

I would welcome your thoughts on this.
I am installing a defib unit for the charity I do work for. it's not a complicated job, just a spur off a RFC, via an unswitched fcu. Basically, the MI says this cabinet(which includes a heater and fan) must be installed on a circuit with RCD protection and have a 13A fuse. There is an option just to put a plug on it, with a 13A fuse, but I am electing to go via an unswitched fcu, and the circuit has rcbo on it. My question is about the cable protection. It is H05RN, so a rubber cable sheath, 3 core, but looking at it I see maybe 0.75 or 1mm at best. I'll check tomorrow, but even at 1mm I think the ccc is maybe 10A max, at 0.75 it is maybe 6A, and it will be installed in conduit. My query is whether a 13A fuse is appropriate. Please let me have your comments on this. As most of you will know, I am not a qualified electrician, but I just feel this is almost "bell-wire" and a 13A fuse won't blow at 13A, more like 20A after a while.
Thank you in advance for your assistance.

 

[Dartlec]

The cable if it's standard H05RN will often have the conductor sizes on it.

I suspect the requirement for 13A may be to allow for inrush current when the defib is deployed? Given that 3A and 13A are the only 'official' ratings, they may have decided the latter is more suitable...

If the cabinet comes as an ready to fit unit with cable, then I'd say that it should be treated as an appliance, and that their requirements should be treated with more weight than if calculating an install yourself. Do they have a technical helpline that could be consulted maybe?

Putting the flex in a conduit would in theory reduce the CCC, certainly, but I'd guess that any heavy 'load' is usually for a very short time, so overload protection of the cable is unlikely to be a huge issue. With RCD protection, I would say that fault protection was covered, so I'd probably go with the MI in this case, rather than risk an issue if it ever has to be used...

Hopefully someone with more experience of actually installing one may be able to pitch in....

 

[DPG]

The cable if it's standard H05RN will often have the conductor sizes on it.

I suspect the requirement for 13A may be to allow for inrush current when the defib is deployed? Given that 3A and 13A are the only 'official' ratings, they may have decided the latter is more suitable...

If the cabinet comes as an ready to fit unit with cable, then I'd say that it should be treated as an appliance, and that their requirements should be treated with more weight than if calculating an install yourself. Do they have a technical helpline that could be consulted maybe?

Putting the flex in a conduit would in theory reduce the CCC, certainly, but I'd guess that any heavy 'load' is usually for a very short time, so overload protection of the cable is unlikely to be a huge issue. With RCD protection, I would say that fault protection was covered, so I'd probably go with the MI in this case, rather than risk an issue if it ever has to be used...

Hopefully someone with more experience of actually installing one may be able to pitch in....

And to be honest I would expect the manufacturer's instructions for something like this would be more accurate than those of the average cheap chinese piece of tat.

 

[Dartlec]

I'd guess they count as a fixed load, in which case overload protection is not necessarily required anyway.

There doesn't appear to be a specific standard for them - though seem to be some voluntary ones.

Presumably this is from a reputable supplier, and not wish.com - in which case hopefully some thought has been given to the electrical design...

 

[timhoward]

Is this one of those heated cabinets that maintains an ambient temperature, and charges up a portable battery powered AED defibrillator?

 

[dodger421]

If it’s anything like the ones we have at work the heater is just to keep the ambient temperature of the cabinet above freezing in the winter and the fan to keep it below 40 C in the summer. All to keep the defib battery in its comfort zone when they’re installed outside on the walls of buildings.

They came with prewired flex and had the same RCD/13A fuse instructions. To be honest the only ones we actually wired in were those on the plant floor where you might as well be outside, the ones inside a heated/ventilated part of the building didn’t get done simply because it wasn’t needed, which was checked with and approved by the distributor and manufacturer.

EDIT to add: Ours are all CardiacScience defibs and enclosures. None of them charge the batteries of the defib, those are integral and are replaceable only, I don’t think they’re rechargeable even when removed from the defib.

There’s a dolls eye indicator on the defib that should be visible through the glass, as should the expiry date of the pads.

 

[pirate]

Thank you @Dartlec. I see this more clearly now. I'll check the cable more carefully in the morning.
Oddly, I wasn't sure how the system worked, and thought the same as you, but now i have learned that the defib package is just that...a transportable pack powered by an internal battery, so it may be grabbed and deployed anywhere.
The cabinet merely has a fan and a heater in it, and doesn;t charge the battery pack in the defib unit, it's simply a vandal-proof cabinet to contain the defibrillator.
Given 3A and 13A fuses are basically the main options, I have to agree that 13A is the way to go here.
I obviously didn't think this through, just got caught up in the idea of such a small cable and a requirement for a 13A fuse.
I appreciate your input...thank you!

 

[pirate]

@timhoward, I thought it would be one that kept an ambient temperature AND charged the battery, but it isn't. I t simply keeps the "defib pack" warm, no charging function, and the batteries are disposable. This will put an extra onus on us (see what I did there?"!)

 

[DPG]

@timhoward, I thought it would be one that kept an ambient temperature AND charged the battery, but it isn't. I t simply keeps the "defib pack" warm, no charging function, and the batteries are disposable. This will put an extra onus on us (see what I did there?"!)

I must admit I assumed they kept the battery charged. So who makes sure the batteries are regularly charged?

 

[dodger421]

I must admit I assumed they kept the battery charged. So who makes sure the batteries are regularly charged?

They don’t need to be regularly charged, they last a very long time when not used.

In fact I know, from experience as a responder, that they can be used for 2 or 3 arrests before needing to be replaced. Those were CardiacScience G3’s I think.

There’s a dolls-eye indicator that changes from green to red when the battery needs replacing.

 

[pirate]

'@dodger421 thank you for your comments here, this is exactly the scenario. We are mounting this on the external wall to allow public access, so the cabinet is vandal-proof, and keeps the defib pack itself at the right temperature to keep the battery and other parts in good condition. I decided to wire it through an unswitched fcu so nobody could accidentally switch it off. I originally assumed a "charging" function but it's simply a replaceable battery pack. Because it is outside the building, the ambient temperature will vary widely. Thus, i will wire to MI and not query further.

 

[pirate]

@DPG and @dodger 421, thank you for your comments. I just thought the battery was charged through the cabinet, and didn't realise the battery life was so long, Thank you all for your incredibly useful comments, and your very swift response to my query. Battery technology has come a long way...
We will have to instigate a monthly regime to check the battery condition, and watch the expiry date of the "shocking" pads too...it's going to be an extra duty, but hey...it's well worth the hassle!
As a charity, we are happy to provide this service for the public, and our members are diligent in their duties, so I hope it will be up and running next week...and i hope it's never needed!
Many thanks again for all the input...really appreciated.
This forum is a great place...

 

[pirate]

Oh, and yes...I promise to ferrule the fs into the FCU!

 

[dodger421]

I believe the battery life is so long because there’s a disconnect switch in the lid of the defib so it’s just self-discharge of the cell that’s happening. Lift the lid and it’s Thunderbirds are go!

Unless it’s getting used regularly by a first responder I’d expect the pads to expire and need replacing before the battery.

 

[littlespark]

I’ve done two defibs now.... and confirm the power supply is for heater only.

Last one I did, there was also a light, but it only came on when dark, and was separately powered by AAA batteries.

 

[pirate]

Tiny update on this. I installed the cabinet today. The cable is H055RR-F. Not easy to work with. Anyway, I installed it as I mentioned before, via an MK FCU which was quite a nice bit of kit.
As I was tidying up, I decided to take the plug which was supplied but not used. Then I saw it had a red printed wiring label on it, and yes, it is fused at 3A. Basically the instructions state a 13A fuse, but if you use the supplied plug it is at 3A. I have emailed the manufacturer for comments.

 

[DefyG]

battery life is so long because there’s a disconnect switch in the lid of the defib so it’s just self-discharge of the cell that’s happening.

Even with constant drain on the battery (ie lithium powered smoke alarms) 10years plus is possible with batteries these days.

 

[pirate]

Another tiny update.
This is the "rating plate" albeit it isn't what you'd expect:

Ok, it's a plastic cabinet, and is stated to be double insulated, but there is a t&e cable into it.
Basically, it's a heater, fan and LED light to confirm status. Printed instructions say a 13A fuse, supplied plug is fused at 3A, which is plenty, imho. I have fitted a 3A fuse in the unswitched fcu.
I then registered it, and that was interesting. The unit is monitored per the details I supplied, and they warn you when the battery or pads need to be replaced, plus there is a visual warning of both of these on the defib unit itself. very clever. Thus, the website monitors it, we can also monitor it, and hopefully it is never needed!
Clearly, the requirement to fuse at 13A for hard-wire is a mistake. I have had no reply so far to my enquiry of the manufacturer. It just seems odd that the DIY instructions are for a plug fused at 3A....and the instructions for hard-wire stress that a qualified electrician should install it with a 13A fuse. What if the cable melted? Would they say that a proper electrician should have ignored the MI and realised it was wrong?
I simply don't know.
Anyway, it's up and running, and as I said, I hope it's never needed. Sorry if I have bored you all with this, but maybe, just maybe, you might come across this particular cabinet, and you will see the anomaly.