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Wire Temp rating - Heater installation

Cruisinga

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Dec 16, 2012
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I am installing this Fahrenheat 5000 watt garage heater in my garage. There is a sticker on the inside of the heater that says "use wire suitable for 75deg C"

The dryer cord that I was planning to use has 60C rated conductors. I have a feeling that on my return trip to HD in the morning there won't be any dryer cords that have 75deg C or better temp ratings.

I suppose I could install with THHN in metal flexible conduit, but I would prefer to use a receptable and plug if possible.

To the pros: how would you go about this?

FYI I am also using this nifty solid state relay to apply a wall-mount low voltage thermostat as I have read the thermostat on the heater drifts as it warms up.
 
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ryanjharvey

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You can always use wire with higher temp ratings but not the other way around. Seems like pipe and wire to a pull-out non fused disconnect and flex and wire to the heater would be cheaper than building a suitable plug/receptacle cord combo.


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Cruisinga

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The 60C dryer cord is brand new and purchased last week. I will check tomorrow morning if there are 75 or higher rated dryer cord because that is the simplest solution for me. The receptacle is already installed
 

Slowgsr

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Subscribing ... my 7' homemade oven needs higher temp wire too. :D. It's awesome to have experts in every industry here.

An electrician wouldn't put a dryer cord on anything well... Except a dryer. Guess that answers your question right?

Get a piece of sealtight, and wire accordingly, you could use an AC disconnect right close to the heater. This would be your transition point from the sealtight to your incoming feed. Should be fed with #10 & 30A
 
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Cruisinga

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Slowgsr- you got me on the dryer cord :)
I picked up some sealtight, #10 THHN and an AC disconnect but two questions to further my understanding-

1. It's a dry location, any reason for seal tight instead of flex metal conduit?
2. The heater is within sight, almost directly above the load panel for the garage. Does the breaker dedicated to this heater qualify as a "disconnect within sight of the heater"? If it does then I guess I could have used the junction box originally intended for the receptacle with wire nuts for the transition from romex to sealtight?
 
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rockwithjason

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Slowgsr- you got me on the dryer cord :)
I picked up some sealtight, #10 THHN and an AC disconnect but two questions to further my understanding-

1. It's a dry location, any reason for seal tight instead of flex metal conduit?
2. The heater is within sight, almost directly above the load panel for the garage. Does the breaker dedicated to this heater qualify as a "disconnect within sight of the heater"? If it does then I guess I could have used the junction box originally intended for the receptacle with wire nuts for the transition from romex to sealtight?
Seal tite looks better and is easier for some people to work with. Flex would work here just as well

I dont have my code book in front of me but generally if an appliance is within fifty feet and in line of sight of the panel then the breaker generally qualifies as a disconnect.
 

cybrdyke

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I dont get it. Almost every electrical supply house carries 10/3 SO cord in a variety of styles. These are rated 90c up to 105c. They'll cut it to length if you ask nice.
Slap on a 30a cord end and you're done. Why are you guys suggesting sealtite and disconnect boxes and all this other stuff?
 

wyliesdiesels

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Modesto, CA
I am installing this Fahrenheat 5000 watt garage heater in my garage. There is a sticker on the inside of the heater that says "use wire suitable for 75deg C"

The dryer cord that I was planning to use has 60C rated conductors. I have a feeling that on my return trip to HD in the morning there won't be any dryer cords that have 75deg C or better temp ratings.

I suppose I could install with THHN in metal flexible conduit, but I would prefer to use a receptable and plug if possible.

To the pros: how would you go about this?

FYI I am also using this nifty solid state relay to apply a wall-mount low voltage thermostat as I have read the thermostat on the heater drifts as it warms up.

A dryer cord with a NEMA 10-50 plug(assuming you bought a 3-wire dryer cord) isnt the right cord plug or outlet to use because a 10-50 is non grounding dual voltage(125v/250v) outlet.

U need a NEMA 6-** plug and outlet for 240v equipment.

I dont get it. Almost every electrical supply house carries 10/3 SO cord in a variety of styles. These are rated 90c up to 105c. They'll cut it to length if you ask nice.
Slap on a 30a cord end and you're done. Why are you guys suggesting sealtite and disconnect boxes and all this other stuff?

Cordage isnt to be used for fixed in place equipment. Cordage is for portable equipment. Sure it will work but it wouldnt be to code.
 
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Slowgsr

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Slowgsr- you got me on the dryer cord :)
I picked up some sealtight, #10 THHN and an AC disconnect but two questions to further my understanding-

1. It's a dry location, any reason for seal tight instead of flex metal conduit?
2. The heater is within sight, almost directly above the load panel for the garage. Does the breaker dedicated to this heater qualify as a "disconnect within sight of the heater"? If it does then I guess I could have used the junction box originally intended for the receptacle with wire nuts for the transition from romex to sealtight?

Yes you could have just made a joint where you intended to put the dryer plug. It's just habit, I always provide a seperate non fused disconnect for almost all types of small devices I install. It's for service, the panel may not be clearly marked, the one doing service may not have been the installer. People and service people can make a big deal trying to find a breaker.

I hardly use aluminum flex, I just keep sealtight and fittings stocked since it covers me for wet & dry situations. Also - it does look nicer I think.

Don't forget to pull a bond in the sealtight.
 

Slowgsr

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Southern ontario
I dont get it. Almost every electrical supply house carries 10/3 SO cord in a variety of styles. These are rated 90c up to 105c. They'll cut it to length if you ask nice.
Slap on a 30a cord end and you're done. Why are you guys suggesting sealtite and disconnect boxes and all this other stuff?

Yeah, cabtire is Mickey mouse.

Only time I used soow for a semi permanent installation is for 600v lift chargers since they do occasionally get moved around, and removed for service. So they technically are not permanently installed since they aren't bolted down

He's going to pay more in material doing it with cord amyways.
 

cybrdyke

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The way the OP states his question, it sounded to me like he's already got the supply run to a receptacle...although it might not be the right one, and he's looking for a piece of cable that's over 60c.
If he gets a 240v 30A receptacle and properly mounts it near the heater, is there any reason that he cant use a cord, say...6' of 10/3 SO with a 30A cap, to plug it in?
I have a similar heater, but only 4000w and it CAME with a 6' 20A cord attached. Is there a difference in code between 20A and 30A?
CD
 
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Cruisinga

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Heater is fixed, here's a pic. Removable would have been nice "just in case" but this works fine. I even learned something in the process.
 

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zmaxmotorsports

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An electrician wouldn't put a dryer cord on anything well... Except a dryer. Guess that answers your question right?

Get a piece of sealtight, and wire accordingly, you could use an AC disconnect right close to the heater. This would be your transition point from the sealtight to your incoming feed. Should be fed with #10 & 30A

:thumbup::thumbup::thumbup::thumbup::thumbup::thumbup:
 

zmaxmotorsports

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I dont get it. Almost every electrical supply house carries 10/3 SO cord in a variety of styles. These are rated 90c up to 105c. They'll cut it to length if you ask nice.
Slap on a 30a cord end and you're done. Why are you guys suggesting sealtite and disconnect boxes and all this other stuff?

Because it looks a lot more professional.:dunno::lol:
 

Slowgsr

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Southern ontario
Your heater looks good. It's good knowing your potentially dangerous appliance has been installed properly without fear of fire & property damage/loss. I dislike portable heaters due to people not respecting clearances, mostly due items in the space being placed close to the heater - not originally where the heater was placed.

Much less chances of this happening in your scenario
 

ryanjharvey

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Louisville, KY
Seal tite looks better and is easier for some people to work with. Flex would work here just as well

I dont have my code book in front of me but generally if an appliance is within fifty feet and in line of sight of the panel then the breaker generally qualifies as a disconnect.

You can use the breaker as the disconnect as long as the panel is within sight and a permanent lockout kit is attached to that breaker - thats how I'm interpreting the 2011 NEC 424.19.
 
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