surge suppressor

Last year our HVAC repair tech recommended that we should get a surge suppressor installed on our furnace/ac unit to prevent damage that might be caused by power sikes or electrical storms. No one else I have talked to in the neighborhood has one of these things. Is it soemthing I should be concerned about?

Reply to
CD
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Hey, if you want to live dangerously, then by all means...........Knock yourself out. Bubba

Reply to
Bubba

Surges that may overwhelm protection already inside all appliances (including the furnace) may occur typically once every seven years. A number that can vary significantly even within same town due to variables such as geology. A survey of the neighborhood may learn more.

Do you install a $100 protector for the furnace? Or do you install something so that everything - including furnace - is protected. When is your smoke detector most important? Maybe during events that create surges. What protects that smoke detector?

This solution has been standard even in telephone exchanges for what

- 100 years? Standard in commercial broadcasting, 911 emergency response centers, etc. In no case is a surge protector called protection. A surge protector is the device that 'connects to' protection. Protection is earth ground.

Ben Franklin demonstrated the concept in 1752. Lightning obtained earth ground destructively via church steeples. How did Franklin divert a surge so that a steeple was not damaged? Lightning rod connected to protection. That protection is earth ground.

Lightning striking a utility wire down the street can be a direct strike to every household appliance including furnace, smoke detectors, and bathroom GFCI. How is protection installed? Just like Franklin's lightning rod, earth a surge before it can enter the building. One protector connected 'less than 10 feet' to an upgraded single point earth ground does what your telco installs to protect their computer. Their computer is connected to overhead wires all over town. Do they put a protector adjacent to the computer? Of course not.

Every incoming wire in every cable must connect to earth ground. Some cables such as cable TV and satellite dish are earthed only by a ground block and wire. Others, such as telephone and AC electric, require a protector to make a 'less than 10 foot' connection. IOW one 'whole house' protector for about $1 per protected appliance verses how much for that furnace protector?

This was long. Many just have trouble learning that earthing - not the protector - is protection. Many assume a protector will somehow stop or absorb what even three miles of sky could not. And yet that is what the protector adjacent to the furnace would do to be useful. That furnace protector also does nothing for smoke detectors, dishwasher, or bathroom GFCIs.

How to installed effective protection? First, building earthing must be upgraded to and exceed post 1990 NEC requirements. IOW all incoming utilities must be earthed to the same electrode (ground rod). Earthing wires to that electrode must have no sharp bends, be separated from other non-earthing wires, no splices, not inside conduit, and all meet as the same earthing electrode.

Second, for utilities that require earthing via a protector, manufacturers with responsible names such as Square D, GE, Leviton, Cutler-Hammer, Intermatic, Siemens, etc manufacturer a 'whole house' protector. Protector must exceed 1000 joules and 50,000 amps. Protectors has a dedicated wire for that essential ('less than 10 foot') earthing connection. Some are sold for less than $50.

Names such as APC, Tripplite, Panamax, and Belkin are not listed. Their protectors don't even have a dedicated earthing wire. How would their products earth as Franklin demonstrated in 1752? Protectors without that earthing wire quietly don't claim to protect from the typically destructive surge - one that may overwhelm protection inside the furnace.

Separation between the protector and furnace is part of a protection 'system'. But more important, distance to earth ground must be as short as practical. That means an earthing wire from breaker box, over top of a foundation, then down to an earthing electrode, is too long. That wire must route through the foundation and down to earthing electrode - short distance and no sharp bends is important.

What will a protector at the furnace do? What is the shortest path to earth? If through a furnace, then the protector may have compromised protection that is already inside that furnace.

Do not yet let anyone promote a protector as protection. Protection is earthing. A protector is simply a connection to earthing. But if that earthing connection is too long, then the protector may earth, destructively, through and adjacent electronics such as a furnace.

Your telephone also needs a 'whole house' protector. Did you know the telco installs one for free? Why? Because a 'whole house' protector is so inexpensive and so effective. But again, you are responsible for providing earthing. Is that telco protector connected short to the same earthing electrode used by AC electric, cable TV, etc? If not, then you still do not have protection.

If not obvious, most important component in this (your 'secondary') protection system is the quality of and short connections to a single point earth ground. Yes - 'secondary'. Also inspect your 'primary' protection:

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An industry professional demonstrates the concept in an application note. All incoming cables connect to a single point earthing (directly or via a protector) before entering the building. Surge protection required even on underground cables:
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A protector will only be as effective as its earth ground. We earth so that a destructive surge, maybe once every seven years, does not enter a building. Therefore protection already inside all appliances (and the furnace) will not be overwhelmed.

Reply to
w_tom

anybody ever tell you that you talk too much?

in the US we don't call it earthing; we call it grounding.

Surges can also occur phase to phase.

I need to get some aspirin.

Reply to
DIMwit

There are earth ground, digital ground, safety ground, a ground between audio components, floating ground, analog ground, counterpoise, equipment ground, and ground inside a mains breaker box. Why a ground wire with no sharp bends, no splices, and not inside conduit? Because ground even at opposite ends of a wire is different.

Also noted were surges made irrelevant by protection inside the furnace controller. Phase to phase surges are irrelevant AND made even less problematic by a single 'whole house' protector that earths typically destructive surges. Protection already inside a furnace controller and other household appliances is not overwhelmed.

Was that post long? Well proven technology is little understood even by electricians if only trained in safety codes - not in the radio frequency energy so common in typically destructive surges. Surge protection involve electrical concepts often not taught to electricians. Note referenced to impedance which is why wire length (not wire gauge) is important.

A furnace protector will only be as effective as its earth ground which is why superior protection is installed where surges would enter a building. Earthing - not a protector - is the protection. Which ground is relevant? In the US, the important ground is a single point earth ground.

Reply to
w_tom

Surge suppressors are normally use across the contacts such as relays contactors and solenoids, purpose of surge suppressors is to limit reveres voltage BkEMF and to limit arcing across the contacts lengthen life of the item and to limit noise on electrical lines. suppressors can help incase of lighting but very much is limited to that, how to limit damage to you appliance from the storms, some one around the Allentown PA. can tell you that only sure way disconnect all. good luck Tony

Reply to
Tony

Snubber circuits are not surge protectors. Arcing only creates noise and may harm contact life expectancy. These are not surges.

Your telco, commercial broadcasters and 911 emergency response center install a 'whole house' type protector AND earthing so that direct lightning strikes never cause damage. Your telephone Central Office may see hundreds of surges during just one thunderstorm - being connected to overhead wires all over town - as even demonstrated by

1950 and 1960 Bell System Technical Journal papers. How often have you been without phone service for 4 days while that computer is replaced? Surge protection is installed for direct lightning strikes

- also making lesser transients irrelevant. Anyone who is suffering appliance damage due to lightning should look at themselves as reason that a protector and sufficient earthing was not installed.

Allentown, being an old industrial town, has many buildings with earthing that does not even meet post 1990 NEC requirements. No earth ground means no effective protection. Earthing that must exceed code requirements. Those who did not upgrade their earthing or thought some magic plug-in protector would protect them must then proclaim, "Nothing can protect from lightning". So why do phones work just fine all through and after the T-storm? Protection from lightning does work when properly located, sized, and earthed.

A 'whole house' protector for even less than $50 is sold in Lowes and Home Depot. Protectors that also include the essential and dedicated earthing wire.

Snubber circuits are for noise. Noise voltages are so low that surge protectors would completely ignore those tiny spikes. Tiny snubbers are not surge protectors.

Reply to
w_tom

Go radio shack buy MOV.

Also buy fuse block--MOV go in line just afer the fuse block.

Could be saves this your ass inna one heartbeat.

Much added to the gleeful situation if /when the lightening actually hits and all your f****ng lowlife neighbors suffer bigtime wherein all you need to do is you have to replace a fuse snip out the cooked MOV.

Yes, definately.

Reply to
Jeffrey Lebowski

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