Chaining extension cords with low voltage devices

[Jackalope]

I know there is a risk of chaining extension cords and everyone recommends against it. But I've also read all extension cords should be temporary and not used for more than 90 days - if you want something permanent you needs to install electrical receptacles (outlets). I know a lot of people use extension cords daily, in fact many extension cords describe using them on a regular basis for office use etc, right on their product description. So, how dangerous are extension cords, really?

Which leads me to the risk involved in my current set up. I am powering some cameras on the sides of my house with extension cords that run through the attic.
Get ready for this! I have a 50ft SJTW 16/3 extension cord that connects to a surge protector which connects to a smaller gauge indoor 15ft extension cord that connects to the camera. The cords are either on top of insulation or draped over roof supports so there is plenty of air getting to them. Each of these cords are rated for 120V. The camera draws 5V of energy.

On a scale from 1-10 how risky/stupid is this? And is checking the cords periodically for heat a way to determine the risk?

 

[James]

risk is not from overload in your case, it’s all about possible damage to cables.

 

[Jackalope]

risk is not from overload in your case, it’s all about possible damage to cables.

How would cables get damaged if not from overload? Do you mean cut or pinched accidentally?

 

[Marvo]

Chained or coiled extension cables can become hot. The risk of damage occuring is increased enormously if the device plugged into them is high current and even more so if the cable is on a roll which means there's no airflow around it to cool it down.

 

[Lucien Nunes]

The advice to avoid extension cords is a 'rule of thumb'. The more weak links in a chain, the higher the risk. Typically, the receptacles on extension cords are not made to the same standard of quality and durability as those on the wall, so there is a greater risk of overheating with high load appliances and of broken ground connections. Long trailing cables are more likely to become split, worn or punctured. If powered from a non-GFCI-protected source, the extra resistance of the ground wire in a long extension can delay the tripping of a breaker in the event of a fault, prolonging an electric shock. Coiled cables can overheat at high load. So rather than trying to get non-technical people to consider all these parameters and how much danger thay add in each application, the received wisdom is simply to avoid extension cords where not strictly necessary.

In your application, with very low current draw and presumably no need of a ground connection, and the extensions not prone to being damaged as they are in the loft, the extra risk is minimal provided they are of good quality, UL-listed etc.

 

[Megawatt]

I know there is a risk of chaining extension cords and everyone recommends against it. But I've also read all extension cords should be temporary and not used for more than 90 days - if you want something permanent you needs to install electrical receptacles (outlets). I know a lot of people use extension cords daily, in fact many extension cords describe using them on a regular basis for office use etc, right on their product description. So, how dangerous are extension cords, really?

Which leads me to the risk involved in my current set up. I am powering some cameras on the sides of my house with extension cords that run through the attic.
Get ready for this! I have a 50ft SJTW 16/3 extension cord that connects to a surge protector which connects to a smaller gauge indoor 15ft extension cord that connects to the camera. The cords are either on top of insulation or draped over roof supports so there is plenty of air getting to them. Each of these cords are rated for 120V. The camera draws 5V of energy.

On a scale from 1-10 how risky/stupid is this? And is checking the cords periodically for heat a way to determine the risk?

My friend the danger in extension cords of that size it is 16 gage wire which is only good for 8 amps which at 120 vac is 800 watts and you are saying that you are going to add them together. The problem I see is the cords in your attic could get hot because every plug in is a weak point. Go at least buy 12 gage drop cords for at least the attic and it shouldn’t get to hot outside in free air. I’m going to be honest with you I think that the 16 gage drop cords should be outlawed. I went to customers house to change a receptacle that had melted into the cord because people don’t understand that the cannot run heaters on these small drop cords to me their dangerous and they cause a lot of fires especially in the winter. Good luck with your project

 

[pc1966]

I'm not familiar with the USA arrangements, but if that extension is only rated at something 8 amps and it is plugged in to an outlet on (presumably) a 15A breaker then in the event of a fault that is a serious risk!

Here in the UK for what you are doing (powering some cameras, so presumable only tens of watts) we would tell you to fit a 3A fuse to the plug (as we have fused plugs rated to 13A) so cable is protected and faults could be cleared fast even with the likely extra resistance, but I don't know if there is anything like that for the USA.

In which case I really wonder whay you would allow a cable that is rated at less then the breaker limit?

 

[Lucien Nunes]

@pc1966 I agree that extensions of lower rating than the circuit fuse are not ideal but they are common throughout the world, so we have a distorted view of things here in the UK with our option to fuse down at the plug. TBH extension leads still get overheated in the UK even when fitted with the correct fuse by running at full current while coiled up.

As the OP's application is to power a camera of a few watts, I don't think the overload scenarios are really applicable to his question. He could power 50 cameras on one extension.

 

[Megawatt]

I'm not familiar with the USA arrangements, but if that extension is only rated at something 8 amps and it is plugged in to an outlet on (presumably) a 15A breaker then in the event of a fault that is a serious risk!

Here in the UK for what you are doing (powering some cameras, so presumable only tens of watts) we would tell you to fit a 3A fuse to the plug (as we have fused plugs rated to 13A) so cable is protected and faults could be cleared fast even with the likely extra resistance, but I don't know if there is anything like that for the USA.

In which case I really wonder whay you would allow a cable that is rated at less then the breaker limit?

@pc1966 the cords are probably on a 20 amp circuit.

 

[Jackalope]

Thanks for the excellent replies.

The cameras take 2-4 watts depending on their state. They are powered, ultimately, by USB connection. I wouldn't consider powering anything more than that, certainly not lights or a heater. All the extensions are UL rated and brand new with no damage.

I feel better about my setup for the time being until I can get some receptacles up there!

 

[Megawatt]

Thanks for the excellent replies.

The cameras take 2-4 watts depending on their state. They are powered, ultimately, by USB connection. I wouldn't consider powering anything more than that, certainly not lights or a heater. All the extensions are UL rated and brand new with no damage.

I feel better about my setup for the time being until I can get some receptacles up there!

I think that you will be fine and I hope you have a great Thanksgiving. Send us some pictures of your project when it’s done