3000w 120v spec silicone heater

aprz · 2 Mar 2021, 00:06

So I’m about to have an a 120v 30amp plug installed to power a fairly large heater 800mmx800mm. The question is how would I earth ground the heater if there’s only two wires(red and black). Also it’s not gonna heat up quickly because from what I read 0.4 watts squared is optimal for a fast heating time. The seller that I purchased it from made it for 3000W 120v setup. I already have the SSR and the TCO switch but just clarifying the specs and how to ground it. As well as if I could use 220v 30A in stead of 120v 30A. From my understanding it would heat up a lot quicker with 220 but if it was made(from my request) for 120v is it still an option for changing mains voltage power source.

fcwilt · 2 Feb 2021, 23:44

You don't ground the heater.

If you are worried about a short you should ground the metal plate you attach it to.

If it is made for 120 you should not use it on 240 without first checking with the vendor.

Question: What does because from what I read 0.4 watts squared is optimal mean?

Frederick

aprz · 2 Feb 2021, 23:59

@fcwilt ok so I’ll stick with the voltage it was designed to be used with and as for the 0.4 watts per square cm

Here’s the link

https://duet3d.dozuki.com/Wiki/Choosing_a_bed_heater

Will be having a electrician install the outlet but making sure on my end I understand if the bed will be able to operate. I’m just wondering if I don’t have to use all 3 prongs on the outlet since it only has two wires.

fcwilt · 3 Feb 2021, 00:02

@1997alex said in 3000w 120v spec silicone heater:

0.4 watts per square cm

Well that makes more sense than what was in your first post.

I’m just wondering if I don’t have to use all 3 prongs on the outlet outlet since it only has two wires.

I would include the ground wire and connect it to the metal plate the heater is going to be mounted on.

Frederick

jens55 · 3 Feb 2021, 02:56

Just a note re using heaters of one voltage at another voltage since this subject comes up frequently .... you don't just double the power by doubling the voltage. Things go up by a factor of FOUR so your 3000W heater is trying to produce 12000 W !!!

Also, for future reference, if you want/need a 3000W heater you should really have specified 240V. There are all kinds of implications of trying to run this at 120V that go well beyond just the actual device. There is a reason why high powered devices such as stoves, hot water heaters and furnaces run on 240V.

fcwilt · 3 Feb 2021, 03:27

@jens55 said in 3000w 120v spec silicone heater:

so your 3000W heater is trying to produce 12000 W !!!

Get out the popcorn!

Frederick

aprz · 3 Feb 2021, 21:09

Well, the worst that could happen is I use the advice and blow up. Just kidding. Will contact some local electricians and see what they think. Thanks, for advice.

aprz · 2 Mar 2021, 21:42

@jens55 Yeah the electrician will be installing a 30A breaker and 30A 120v outlet. It’s going to be 120v. The total amperage is at max 25A for a 3000w device on 120v. I know electricity isn’t something to mess around with but I like talking about it and discussing the theory behind it and my madness. Will let you guys know how it turns out.

warpster · 3 Feb 2021, 21:45

Ground the metal bed so if the heater shorts to the bed it will blow the circuit breaker instead of electrocuting you when you touch the bed after it is shorted, and standing in water. By the way you can use the ground from the power supply cord if it is three pronged to ground the bed. Ground is ground....

theruttmeister · 3 Feb 2021, 21:56

Silicone encapsulated wire heaters are double insulated (making them suitable for use in Class II electrical devices) and as such do not need to be earthed.

A short to the metal bed would require something catastrophic, like the entire heater catching fire, or someone running a drill bit through the bed and the heater.

If you are going to earth the bed, you also MUST earth the frame, the hotend, basically everything metal on the machine. Those earth bonds should be appropriately sized (so that the fuse for the device, 30A, blows before the earth bond(s) burn out).
You should also probably implement an annual in-service inspection and testing protocol. The UK standard is PAT-testing and is terribly dull and mostly involves cutting the plug off of devices that can't be correctly identified by the technician.
Like kettles.
/s

Personally I'd be more worried about the plug. US 30A plugs are garbage and a fire waiting to happen.
(Ok, all American plugs are a fire waiting to happen).

zapta · 4 Feb 2021, 00:43

@1997alex said in 3000w 120v spec silicone heater:

but if it was made(from my request) for 120v is it still an option for changing mains voltage power source.

You can have 240VAC power in US homes. https://www.youtube.com/watch?v=iby2wDNFk6o

If you want your heater to be dual voltage you may want to order it with a center tap or just use two identical heaters that you can either connect in serial (for 240V) or parallel (for 120V), or maybe four standard heaters will cover your bed just fine.

In any case, be careful, it can kill you.

fcwilt · 4 Feb 2021, 00:57

@zapta said in 3000w 120v spec silicone heater:

In any case, be careful, it can kill you.

Well, just a little.