diff --git a/sources/bomexport.cpp b/sources/bomexport.cpp
index ef5581016..a84bb51b2 100644
--- a/sources/bomexport.cpp
+++ b/sources/bomexport.cpp
@@ -59,8 +59,27 @@ QStringList BomExport::defaultColumns()
 
 QString BomExport::defaultQuery()
 {
+		//Slaves and terminals are included because both are routinely
+		//separately orderable hardware. A circuit breaker can carry ten or
+		//twenty auxiliary blocks, each with its own order code, and a
+		//terminal block is a purchased part in its own right. Neither shares
+		//a line with its master: the query is ungrouped, one row per element,
+		//so each appears as the distinct item it is.
+		//
+		//Anything that should not be ordered is kept out by setting
+		//exclude_from_bom on the element, which the view already honours --
+		//a relay's own auxiliary contact, say.
+		//
+		//Thumbnails are deliberately left out for now even though ten of
+		//them in the shipped examples carry manufacturer and reference data
+		//(the assembly-plan mounting-plate symbols), because that has not
+		//been asked for and is a separate question. The folio report arrows
+		//and the conductor definition stay out because they are not hardware.
+		//
+		//See discussion #847.
 	return QStringLiteral("SELECT %1 FROM element_nomenclature_view "
-						  "WHERE ( element_type = 'simple' OR element_type = 'master') "
+						  "WHERE element_type IN "
+						  "('simple', 'master', 'slave', 'terminal') "
 						  "ORDER BY diagram_position, position, label")
 			.arg(defaultColumns().join(QStringLiteral(", ")));
 }
diff --git a/sources/dataBase/projectdatabase.cpp b/sources/dataBase/projectdatabase.cpp
index df686fe12..bd0f0069d 100644
--- a/sources/dataBase/projectdatabase.cpp
+++ b/sources/dataBase/projectdatabase.cpp
@@ -711,7 +711,14 @@ void projectDataBase::createElementNomenclatureView()
 							//the table's. Kept identical to the mask populateElementTable()
 							//used to apply, so what this view returns does not change --
 							//a slave element (a relay contact) is still not a line item.
-						 " AND e.type IN ('simple', 'terminal', 'master', 'thumbnail')");
+							 //Slave is here because an auxiliary contact block is
+							 //separately orderable hardware with its own part
+							 //number, even though it shares its master's BMK.
+							 //Anything that should not be ordered -- a relay's
+							 //own auxiliary contact, say -- is kept out by
+							 //exclude_from_bom above, not by its base type.
+							 //See discussion #847.
+						 " AND e.type IN ('simple', 'terminal', 'master', 'slave', 'thumbnail')");
 
 	QSqlQuery query(m_data_base);
 	if (!query.exec(create_view)) {
diff --git a/tests/qttest/tst_smart_device.cpp b/tests/qttest/tst_smart_device.cpp
index b054a6eba..ced7ecbdc 100644
--- a/tests/qttest/tst_smart_device.cpp
+++ b/tests/qttest/tst_smart_device.cpp
@@ -92,9 +92,17 @@ void SmartDeviceTest::defaultQueryAndCsv()
 					QStringLiteral("日本電機")));
 		QVERIFY(add(QStringLiteral("-K1"), QStringLiteral("master"), 1, 2,
 					QStringLiteral("Müller")));
+		//A slave and a terminal are both separately orderable hardware -- an
+		//auxiliary contact block has its own order code, and so does a
+		//terminal block -- so both belong in the bill of materials. See
+		//discussion #847. Anything that should not be ordered is kept out by
+		//exclude_from_bom rather than by its base type.
 		QVERIFY(add(QStringLiteral("-K1.1"), QStringLiteral("slave"), 1, 3,
-					QStringLiteral("Must not be exported")));
+					QStringLiteral("Aux contact block")));
 		QVERIFY(add(QStringLiteral("X1"), QStringLiteral("terminal"), 1, 4,
+					QStringLiteral("Terminal block")));
+		//Still filtered out: a folio report arrow is not hardware.
+		QVERIFY(add(QStringLiteral(">1"), QStringLiteral("next_report"), 1, 5,
 					QStringLiteral("Must not be exported")));
 
 		QSqlQuery query(db);
@@ -103,11 +111,13 @@ void SmartDeviceTest::defaultQueryAndCsv()
 		int rows = 0;
 		const auto csv = BomExport::toCsv(
 				query, BomExport::defaultColumns(), true, &rows);
-		QCOMPARE(rows, 2);
+		QCOMPARE(rows, 4);
 		QVERIFY(csv.startsWith("\xEF\xBB\xBF\"label\";\"designation\";"));
 		QVERIFY(csv.contains(QStringLiteral("Müller").toUtf8()));
 		QVERIFY(csv.contains(QStringLiteral("日本電機").toUtf8()));
 		QVERIFY(csv.contains("\"Quoted \"\"note\"\"\nnext line\""));
+		QVERIFY(csv.contains("Aux contact block"));
+		QVERIFY(csv.contains("Terminal block"));
 		QVERIFY(!csv.contains("Must not be exported"));
 		QVERIFY(csv.indexOf("-K1") < csv.indexOf("-K2"));
 	}