electric clothes dryer

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I had a service guy tell me that sometimes electr. boards fail inside the dryer due to electrical spikes. I wondered if this was BS because this is a 220 appliance and I didn't think they are as sensitive to such things. If it is true, can you buy a surge protector just for the clothes dryer? Thoughts on this...
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Did the board in your dryer fail, or is this a hypothetical question? If it did fail, I'd be more suspect of lead-free soldering than a voltage spike. Circuit boards are not directly line-powered. I think the dangers of spikes, in general, have been overstated by 3-4 orders of magnitude. But I don't think a 220 volt unit is any less vulnerable than a 120 volt unit.
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Spikes come in on the power lines and don't care about the voltage, so it's certainly possible that one can damage a 220 volt appliance just like a 120 volt model. Yes, you can buy 220 volt surge protectors -- do a Google search. Another choice is to wire a surge protector in at the main breaker and protect the whole house.
Tomsic
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* I believe this to be true. It seems as though microprocessor controlled appliances fail earlier than their mechanically controlled predecessors.
Steps you can take to help reduce the risk of this is making sure that your grounding electrode system is in good condition. Check your ground clamps at the water pipe and ground rods (If visible) for corrosion and tightness. Here's a photo example from my site of a clean connection: http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#NewWaterPipeGroundClamp
Make sure your water pipes are bonded to each other: http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#CloseShotWaterHeater
Have a bonding jumper across the water meter: http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#WaterMeterWithJumper
You should also install a surge suppressor in the main electrical panel.
The grounding and bonding will help protect against lightning strikes and the surge suppressor will help protect against spikes as a result of other equipment, particularly those that are motor driven.
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That's the best and most cost effective solution. And of course voltage spikes can damage a 240V dryer with electronics just like a 120V microwave. Lightning hitting the utilities could sends a 3000V spike down the lines. 3000V going into something designed for 240V is just about as bad as it going into a 120V appliance.
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On 10/5/2012 7:02 AM, snipped-for-privacy@optonline.net wrote:

I agree a service panel protector is a real good idea.
If you have a strong surge from lightning on the power service it likely lifts both hot wires above ground. Since the neutral is bonded to ground and the earthing system at the service I would guess that surges line-to-line are smaller than line-to-neutral or ground, but they easily could damage 240V equipment.
If you have no service panel protector and you have a strong surge, at about 6,000V there is arc-over from the service panel busbars to the enclosure. After the arc is established the voltage is hundreds of volts. Since the enclosure is connected the the earthing system that dumps most of the surge energy to earth. Surge protection at the equipment is likely to have more problem with a 3000V surge than one that is much stronger.
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wrote:

Any decent protector will shunt spikes line to neutral and line to line. (3 or more MOVs) In the dryer, they usually connect the motor and the controller board line to neutral. I bet this happened when the dryer was off and the only thing connected was the circuit board.
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On Fri, 05 Oct 2012 12:11:25 -0400, snipped-for-privacy@aol.com wrote:

Repair guy said that most newer dryers were hot wired to timer not control knob like this older one was. He did say that when it was off, the power was still going to the control knob so if I understand you correctly, you sound correct.
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John Grabowski wrote:

http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#NewWaterPipeGroundClamp
http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#CloseShotWaterHeater
http://www.mrelectrician.tv/questions/Question-OldCableTVGround.html#WaterMeterWithJumper
Diligent bonding and connections to water pipes is good, but it's not a substitute for a proper ground, e.g., one or more copper rods driven six feet or more into the earth. A water-pipe bond is just to prevent the piping systems in the house from remaining live with voltage if they come in contact with a live wire.
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*I took for granted that the OP had a copper pipe water service from the street. You are correct that if he didn't, two eight foot ground rods would provide the necessary lightning protection.
John G
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John Grabowski wrote:

I suggest that no amount of copper pipe is a proper substitute for ground rods.
What's the reference to lightening protection about?
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Lightening is what Michael Jackson did to his skin. You mean lightning I think!!!
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wrote:

That is not really true if you are talking about the all metal water systems in days of old. The whole city is a grounding grid with miles of electrode in the dirt.
These days it is hard to find a new metal water pipe.
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*So in your mind 16' of copper plated iron rod is a better ground than the copper pipe that runs from a house out to the street and is connected to a giant web of piping.

*The primary purpose of a grounding electrode (Water pipe, ground rod, ground ring, ufer ground, copper plate, etc.) is for voltage stabilization and lightning protection.
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John Grabowski wrote:

Of course.
You may be confusing a proper electrical ground with the grounding of the plumbing system.

Sigh. A water pipe is not a grounding electrode. It may FUNCTION as one, but using a water pipe is not best practice.
As an aside, how can more than five things be a "primary" purpose?
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wrote:

Primary purpose is PROTECTION.
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On 10/6/2012 10:42 AM, HeyBub wrote:

Ground rods are the worst earthing electrode.

You are just confused.

A metal municipal water system will be a far lower resistance to earth than any other earthing electrode you will have a house.
It certainly is a good earthing electrode, which is why the NEC has required its use since time began.
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bud-- wrote:

Perhaps this will explain:
"You've probably seen project requirements that call for the grounding of piping systems and exposed structural steel. Those requirements, although well intended, miss the mark. The stated intention of such requirements is nearly always the removal of dangerous voltage on specific types of metal parts in the event of a ground fault. These metal parts include exposed structural steel members, electrically conductive metal water piping systems, metal sprinkler piping, metal gas piping, and other metal piping systems. But these requirements fail to make that intention a reality. That's because you remove dangerous voltage on metal parts through bonding, not through grounding."
and
"The NEC (section 250-81 through 250-83) requires that the electrical system connected to all of the following, if available for grounding purposes: * metal frame of building * concrete encased electrode (rod, pipe, plate, braided wire) * ground ring and * metallic water pipe with 10 lineal feet in contact with earth
The NEC has noted that metal piping will corrode over time and possibly lose its continuity with the soil (i.e. ground) or be replaced by plastic pipe. Accordingly, should this occur, the NEC has mandated the 3 other paths to ground be utilized."
In other words, attaching a metal water pipe to an earth ground is used to protect the user from the plumbing, not to provide a ground for the electrical system. Using metal water pipe as an electrical ground is insufficient.
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On 10/7/2012 3:01 PM, HeyBub wrote:

No source.
I am not fond of the term "grounding" because you may be talking about "bonding" or "earthing". Your quote has that problem. (The NEC has started to clarify which use is intended.)
The NEC has 3 electrodes that are *required* to be used as earthing electrodes (where present). One is metal water service pipe (10 ft...). Another, in general, is structural steel (because of its connection into the rebar systems in the concrete foundation).
Your source is incorrect - water pipe and structural steel *must* (in general) be used as earthing electrodes.
If they are connected as earthing electrodes they are also "bonded".

The correct list has electodes that may already be present in a building and does not include ground rings and everything after "concrete encased electrode".

Cite for corrode. Cite where water pipe has worse corrosion problems that ground rods.
The NEC has NOT mandated that "3 other paths" to earth be utilized.

The requirement to use water pipes as an earthing electrode is in a section on the earthing system and the electrodes to be used. It is in your list of required earthing electrodes, above.
You have bullsiht information and are using a bullsiht source.
(What a surprise.)
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bud-- wrote:

Sorry. I thought the material was righteous on its face. Evidently not. See:
"Grounding vs. Bonding - Part 10 of 12" http://ecmweb.com/bonding-amp-grounding/grounding-vs-bonding-part-10-12

"Your source is incorrect..."
Giggle

Does not exactly satisfy your request, but of interest: "The NEC has noted that metal piping will corrode over time and possibly lose its continuity with the soil (i.e. ground) or be replaced by plastic pipe. Accordingly, should this occur, the NEC has mandated the 3 other paths to ground be utilized." http://www.ct.gov/dph/lib/dph/environmental_health/private_wells/37_Electrical_Grounds_-_A_Controversial_Necessity.pdf

Yes it has. (See above)

I assume your "non-bullshit" source is your own dim remembrance of things past.
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