220V ac Heated Bed

Guys i want to change one of my heaters and instead of a 12v heater to install a 220v . The thing is that i kind of afraid a failure (short circuit) and the possibility to burn out the duet . So i wanted to ask the users that runs 220v heaters if there are any precautions that i could take to eliminate a possibility of a short circuit.

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Delta Printer
Duet 0.8.5 firmware 1.19

You need a SSR (solid state relay), this will isolate the 220v heating circuit from the LV circuit on the Duet.

You will need to configure your duet for on/off control, and when you wire up the SSR and heat bed make sure you don't cut corner, good quality connections and good insulation are required.

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Quote
bgkdavis
...and when you wire up the SSR and heat bed make sure you don't cut corner...

i am not sure what you meant by this .

Quote
bgkdavis
...good quality connections and good insulation are required...

the insulation is what i afraid most and basically i was wondering if there is anyway to protect the duet if something fails from ac going through it .

when i ll do it i ll ask in the duet forum about the configuration . i also have some ssr modules

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Delta Printer
Duet 0.8.5 firmware 1.19

Quote
Gaou

Quote
bgkdavis
...and when you wire up the SSR and heat bed make sure you don't cut corner...

i am not sure what you meant by this .

Quote
bgkdavis
...good quality connections and good insulation are required...

the insulation is what i afraid most and basically i was wondering if there is anyway to protect the duet if something fails from ac going through it .

when i ll do it i ll ask in the duet forum about the configuration . i also have some ssr modules

What I mean is don't use cheap wire not rated for AC, make sure that all connections are well made and you cant make contact with any conductive surfaces.....actually scratch all this, if you really have to ask and really dont understand the precautions you need to take when working with 220VAC then you need to get it done by a competent electrician or stick with 24VDC

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Hi Gaou,

Is this on your RRP Mendel? If so, I'd personally recommend you stick with the 12 V heater which is adequate for your small bed. The biggest hazard is that the bed moves back and forth so the heater wire is being flexed all the time. If it breaks with 12v running through it, it won't do much harm. If it's 220v and breaks and a live wire touches part of the frame, it could kill you. If you really need a bigger heater, you could consider using a 24v one but 220V AC main on a bed that size is just overkill (excuse the pun).

i have two mendels and the second one has a bed of 260mm x 260mm. at this time i am using a 12v 200mm x 200mm heater but it is too small for the printer so i thought that i have to replace it . the 24v was my first thought as it is easier to setup but it requires a 24v psu which i don't have and it cost . So i thought that a ac heater would be a lot cheaper to set up . the wires isn't what i am worrying about as i can protect them with a flexible plastic tube.

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Delta Printer
Duet 0.8.5 firmware 1.19

Quote
Gaou
the wires isn't what i am worrying about as i can protect them with a flexible plastic tube.

Are you sure?

Is the tube specifically rated for insulating AC cabling (ie conduit)?

Will you have adequate separation between the AC power cables and the DC signal cables to prevent inducted noise?

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD