I'm helping a friend of mine who wants to install a Panamax GPP8005
whole house surge protector, which gets mounted next to the main
panel. The instruction say it can be connected to the main panel
using either a double 30 amp breaker or preferably using a sub-feed
The picture of the unit shows it with wires coming out, ready to be
attached. So, I understand the connection method using the
breakers. But, if we followed the directions and connected it using
a sub-feed lug kit, wouldn't that be a major code violation? The
only protection then would be the main panel 150 amp breaker, which
would be incompatible with whatever gauge wires are coming out of the
surge protector, because if they can connect to a 30 amp breaker, they
surely can't handle 150 amps. So, am I missing something here?
Here's the install instructions and pics if you want to look:
I did not see what size wires were being used , but if they are # 10 or
larger (one refferance did seem to give the impression of # 6) They should
be large enough. They only have to be able to carry the current long enough
to blow the main breaker. That should only take a a second or so, not
hours as if the thing was actually using any power so to speak of.
The Siemens article also includes TVSSs (transient voltage surge
suppressors) which were covered by NEC article 285. That is what you
have. They must be connected downstream from over current protection
(article 280 "surge arresters" can be connected ahead of the service
NEC articles 280 and 285 were reorganized in 2008. In one of the changes
TVSSs are now called SPDs (surge-protective devices) - still under
SPDs are covered by UL1449. Since the "second edition", which was
effective in 1998, SPDs (both plug-in and service panel) have been
required to have protection built in to disconnect failing MOVs. It
commonly responds to overheating MOVs and may also include fuses. The
internal protection will protect the wires.
Minimize the wire length and avoid sharp bends. The clamp voltage is
higher the longer the wires are because of voltage drop through the wire
impedance, which is significant for surges. If wires are fairly long
lightly twisting them is a good idea. The rated clamp voltage is for 6"
lead length for SPDs made now. The IEEE guide at
talks about lead length starting document page 22.
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